Wireless carriers' failure to fully restore cellular service in Florida after Hurricane Michael "is completely unacceptable," Federal Communications Commission Chairman Ajit Pai said today in a rare rebuke of the industry that he regulates.

Verizon in particular has been under fire from Florida Governor Rick Scott, who says Verizon hasn't done enough to restore service. By contrast, Scott has praised AT&T for its disaster response.

The FCC will open an investigation into the post-hurricane restoration efforts, Pai said. Pai and Scott urged wireless carriers to immediately disclose plans for restoring service, waive the October bills of affected customers, and let customers switch providers without penalty.

Pai's statement didn't name specific carriers. but Verizon seems to be struggling the most to restore service, based on criticism from the governor. Verizon was the only wireless carrier mentioned specifically by Scott today in a statement that called on telecom companies to "treat Floridians fairly."

Gov. Scott suggested that Verizon has misled the public about its progress in restoring service. He said:

Verizon recently said in a press release that 98 percent of Florida has service. This statement, which includes customers in Florida that were hundreds of miles away from impacted areas, does not help Florida's law enforcement in Bay County and families communicate with loved ones in Panama City and does not help those needing medicine call their pharmacy in Lynn Haven.

Pai's statement said that carriers haven't shown enough "urgency" in restoring service:

Even though efforts to restore communications services have been going well in most of the areas affected by Hurricane Michael, the slow progress in restoring wireless service in areas close to where the hurricane made landfall is completely unacceptable. While the FCC has been in regular contact with companies serving the affected areas, I'm concerned that their actions on the ground aren't matching the urgency that we have conveyed during those conversations. I am therefore joining Gov. Scott in calling on wireless carriers to waive the bills of Floridians in these affected areas for the month of October and to allow them to change carriers without penalty. These carriers also need to immediately disclose publicly to Floridians how they will quickly restore service. In addition, I have directed our Public Safety & Homeland Security Bureau to promptly initiate an investigation into this matter.

Verizon offers three months of credits

Verizon announced shortly after Pai's statement today that it will give three months of free mobile service to "every Verizon customer in Bay and Gulf counties."

"Verizon is 100 percent focused on repairing our network in the Florida Panhandle," the company said in a press release. "We are making progress every hour, and we expect that trend to continue at a rapid pace. We won't rest until service is completely restored."

Verizon also said on its hurricane update page today that it brought two new cell sites into service overnight, but the company did not say when connectivity will be fully restored.

Verizon faced another disaster-related public relations problem in August. That's when the Santa Clara County fire department said Verizon throttled its unlimited data plan while it was fighting California's largest-ever wildfire.

AT&T told Ars that its pre-storm preparations allowed it to "keep our customers, including first responders, connected during and after the storm in many areas."

"Before the storm hit we announced and implemented credits for our customers," AT&T also said. "Beginning on October 10, credits have been given to customers in Bay, Calhoun, Franklin, Gulf, Liberty, Taylor, and Wakulla counties. We plan to continue extending these credits through October 21 and will continue as conditions require. Our crews continue working day and night to ensure continuing connectivity for the affected areas." AT&T is providing network updates at this page.

T-Mobile CEO John Legere tweeted that his company's "network has been largely restored in the Gulf and Bay counties, including Mexico Beach." T-Mobile is providing free service as of October 10, waiving fees for device replacements, and "waiving any fees for customers coming to or leaving T-Mobile," he wrote.

Sprint said today that it is waiving "call, text and data overage fees" from October 10 to October 18.

Governor faults Verizon, praises AT&T

Verizon has said that the fiber lines providing bandwidth for its wireless network suffered "unprecedented damage," making it harder to restore cellular service.

The FCC's latest post-hurricane status update, released today, said that 12.7 percent of cell sites in Florida's disaster zones were still out. The outage rate was highest in Bay County, where 61.5 percent of cell sites (201 out of 327) were out.

Scott met with Gadsden County officials and "again expresse[d] frustration with Verizon's hurricane response and sa[id] customers should be released from contracts so they can get service from AT&T," Tallahassee Bureau Chief Steve Bousquet of the Tampa Bay Times tweeted today.

In a tweet on Saturday, Gov. Scott thanked AT&T "for working to get communications back online quickly & helping Florida communities following Michael."

Still, Scott said AT&T's network was having problems in some areas, according to a Washington Post article published Sunday. "We have an unbelievable problem in Bay County—Verizon is down and AT&T is up, but the county services are on Verizon. In other places, Verizon is up and AT&T is down," Scott said.

Florida CFO & State Fire Marshal Jimmy Patronis was on CNN Friday, and he said the governor was distributing AT&T phones to public safety officials because of Verizon's network failures.

"Verizon Wireless does not exist in Bay County anymore. It was the dominant carrier, so nobody has the ability to communicate," Marshal Patronis said in the CNN interview. "If you've got T-Mobile or AT&T, you're able to get a call out. Gov. Scott, earlier today—he bought 400 AT&T cellular phones just to pass out to our sheriff's departments and first responders just to simply allow communication to get somewhat functional between these different agencies trying to save lives."