Story highlights Hooters, other businesses say Bob Filner is persona non grata

Filner's official credit card bills under scrutiny amid complaints

The San Diego mayor has been accused of sexually harassing numerous women

Filner answers recall petition drive: "Now is not the time to go backwards"

How bad has it gotten for embattled San Diego Mayor Bob Filner?

Even Hooters -- the restaurant chain sometimes criticized for its scantily clad waitresses -- says he's no longer welcome.

The chain's downtown location has joined a campaign by a local radio talk-show host, who's urging businesses to post signs in their window that declare Filner persona non grata. The signs note that the mayor "will not be served in this establishment" and "We believe women should be treated with respect."

In a statement posted on Twitter, the company said restaurant acted on its own.

"Our Hooters Girls in San Diego have spoken. Not a corporate gig, but we support our girls," it read.

Refusing to resign in the face of mounting allegations that he groped and made lewd comments toward numerous women, Filner is facing an effort to recall him from office. And now a city councilman wants him to answer questions about more than $500 in charges on his official city credit card from a downtown hotel.

JUST WATCHED San Diego mayor's history kept quiet? Replay More Videos ... MUST WATCH San Diego mayor's history kept quiet? 02:36

JUST WATCHED San Diego Mayor Out of Therapy Replay More Videos ... MUST WATCH San Diego Mayor Out of Therapy 03:36

JUST WATCHED 9th accuser: Filner grabbed my derrière Replay More Videos ... MUST WATCH 9th accuser: Filner grabbed my derrière 03:42

"When you see statements like this, it raises the question of is city business being done or not," Councilman Kevin Faulconer said Tuesday.

CNN obtained Filner's municipal credit-card statements from January to May. The taxpayer-paid card included charges ranging from less than $30 to about $111 at the Westgate Hotel, including one incurred on a Sunday.

The Westgate is across the street from the mayor's office. Regulars at the bar who did not want to speak on-camera told CNN that Filner was often here, usually with a different woman.

Faulconer, a Republican who sits on the council's audit committee, raised questions about other charges as well -- $3,000 to an online reputation-management firm, $128 for a juicer and a $30,000 trip to Paris. He said Filner has promised to reimburse the city for that trip, but there has been no proof of a refund.

The 70-year-old Filner was elected mayor of the eighth-largest American city in 2012, after 10 terms in Congress. His accusers range from a singer at a campaign fundraiser to his former communications director, who called him unfit for office.

He's rebuffed calls to resign from all nine City Council members and from his fellow Democrats, including California's two U.S. senators. He now faces a recall effort that is trying to gather more than 100,000 signatures needed to put his future up to a new vote, though some political observers doubt organizers can succeed.

Filner issued a required response to the notice of a petition drive Tuesday, arguing that voters should weigh his administration's push for new parks, high-tech jobs, better roads and a 2024 Olympic bid before they decide to whether they want to turn him out of office.

"Now is not the time to go backwards -- back to the time when middle-class jobs and neighborhood infrastructure were sacrificed to downtown special interests," Filner said in a written response to a proposed recall petition. "We need to continue to move forward!"

But Michael Pallamary, the head of the recall effort, said Filner "obviously believes his policy initiatives excuse his being a sexual predator."

"His reply is unacceptable," Pallamary said. "San Diegans want a mayor that doesn't grope and demean women, who doesn't abuse his office to satisfy a perverted quest for a sense of power, and who has the ability to lead our great city -- an ability Filner can never, ever reclaim."

Filner has brought "great shame" on the city, Pallamary said, vowing, "We will recall him from office."

In July, Filner acknowledged that he "failed to fully respect the women who work for me and with me" and that he was "embarrassed" by his actions. But he also said he will be vindicated by "a full presentation of the facts" and he will not resign.

"We have moved toward the vision of producing thousands of middle-class jobs in our port; creating a solar-based city to enhance our environment and create jobs; building an efficient international border to bring billions of dollars into our economy; keeping our military and hi-tech sectors strong and vibrant," Filner said in response to the recall petition notice. He touted new support for the arts, a five-year labor agreement with city workers and work toward bringing the summer Olympics to the city.

The mayor entered a two-week intensive behavior therapy program on July 29, but his attorney, James Payne, said Filner was able to complete that phase of treatment by Saturday. He'll continue with outpatient treatment, Payne said -- but he might not be back at work in his office anytime soon. His chief of staff changed the locks, according to numerous reports, including one by CNN affiliate KFMB

And after weeks of complaints, some observers are questioning whether more should have been said about Filner's behavior before last year's election.

"I think there was a lot of whispering," former state Assemblywoman Lori Saldana told CNN. "It was a lot of things under the surface. A lot of 'boys will be boys.' "

Saldana said she brought complaints about Filner to San Diego County's Democratic Party leader two years ago after hearing accounts of harassing behavior from six women. Nothing happened, she said.

"It was considered abusive. It was insulting at times. And I think people need to pay attention to those reports, and it didn't happen two years ago," said Saldana, also a Democrat.

Filner's 2012 opponent, City Councilman Carl DeMaio, hinted at the issue during a mayoral debate. Video of the event shows DeMaio telling voters, "You need a mayor who's going to insist on zero tolerance of sexual harassment in the workplace" -- turning to look at Filner while he makes the comment.

DeMaio is now running for Congress and had no comment. But his mayoral campaign featured a television spot in which an Washington airport worker who had a run-in with Filner described his actions as "scary and hostile."

"I deal with frustrated travelers every day, but I never came across anyone like Bob Filner," she said.