Cory Tschogl says she has an Airbnb squatter - a guest who rented her Palm Springs vacation condominium, then stopped paying rent, refused to leave and threatened her with legal action.

"It's a horror story," said Tschogl, 39, who lives in San Francisco.

It's also a cautionary tale, illustrating the tenuous nature of new marketplaces that let people rent homes or rooms to strangers.

Although Airbnb and similar platforms use reviews of hosts and guests to try to weed out bad players, and require credit card information from guests, those systems are far from ironclad. And although Airbnb has a $10 billion valuation and handles more than 600,000 temporary rentals worldwide, it's still a startup whose customer service sometimes seems to lag.

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Tschogl said she begged Airbnb for help through numerous e-mails and phone calls without getting much assistance.

Now she's hired a lawyer, who will cost several thousand dollars and take three to six months to evict the tenant, who now has renters' protections under California law because he has occupied the unit over 30 days.

Similar issues can arise with any tenants, of course, whether they book through Airbnb or find a place through the classifieds.

"Our initial response to this inquiry didn't meet the standards we set for ourselves and we've apologized to this host," said Airbnb spokesman Nick Papas in a statement. "In the last week, officials from our team have been in incredibly close contact with this host and she has been paid the full cost of the reservation and we're working with her to provide additional support as we move forward."

Tschogl, who works as a rehabilitation therapist for blind and low-vision people, was priced out of the San Francisco housing market, so she bought a one-bedroom condo in a gated Palm Springs community 18 months ago. She visits it often and her father lives nearby.

Income has helped

She's rented it occasionally through Airbnb and Flipkey for about a year. The income from guests who paid around $450 a week helped meet her expenses for the mortgage, taxes and insurance.

But her current tenant's stay had issues from the beginning.

"When he first checked in, he complained about the tap water - it's hard water with minerals because it's in the desert," Tschogl said. "My gut alarm-bell went off. I agreed to give him a full refund, not even charging a cleaning fee. But then he changed his mind and decided to stay."

The guest booked the space for 44 days from May 25 to July 8 and paid for the first month in advance through Airbnb. After 30 days, Airbnb notified Tschogl that its attempts to collect the balance due "did not succeed" without specifying why. The company eventually paid her the two weeks' missing rent.

After numerous e-mails and calls from Tschogl, Airbnb offered to pay for the man to stay at a hotel for 30 days, but said he didn't respond to e-mails and his phone was disconnected.

Once the 44 days were up, Tschogl texted the renter that his reservation contract was over and that the power would be shut off in 24 hours.

The guest texted back saying he was legally occupying the condo and that loss of electricity would threaten the work he does at home that brings in $1,000 to $7,000 a day.

The texts threatened to press charges for "blackmail and damages caused by your negligence and malicious misconduct, including $3,800 PID Espresso machine as well as medical bills for my brother's hospital visit after he got sick here drinking unfiltered tap water."

Tschogl realized that she couldn't legally cut off the electricity, although her SoCal Edison account showed daily usage was triple to quadruple normal. Her father went by the unit several times and photographed it with the sliding glass doors and windows wide open, presumably while the air conditioning was going full blast to combat the 114-degree heat.

The guest, whose Airbnb "verified ID" says he is from Austin, Texas, did not respond to e-mail requests for comment and his cell phone did not accept messages.

"Airbnb made the whole process much more complicated than it needed to be," Tschogl said. "They were almost absent. There was no phone number or direct contact e-mail. I got e-mail responses only every 24 to 48 hours."

Copies of her e-mails with Airbnb, reviewed by The Chronicle, showed several delayed answers, for which the customer service representatives apologized. The company became more responsive after Tschogl's sister, a music executive, tweeted a stream of complaints about it in early July.

After The Chronicle contacted Airbnb, the company stepped up its assistance, Tschogl said. That included an e-mail saying "We're prepared to assist with your legal fees ... so we can help alleviate the financial stress caused by the stay."

Positive overall

Tschogl said her previous Airbnb experiences, both as a guest and a host, were positive.

"I understand that Airbnb is an emerging company, and I like the idea of it," she said. "However, I don't think they're equipped to deal with this type of situation. I'd like to see them change some policies and improve customer service so they can help people should something like this happen."