Customers switched to Frontier Communications from Verizon in Florida, California and Texas continue to complain they are being overcharged for service, sometimes by hundreds of dollars a month, and they’re fed up.

Danielle Ferrari, owner of a clothing and consignment shop in Tampa, has been battling the phone company over its erroneous billing since the first day it took over service from Verizon Communications.

“The very first bill was wildly wrong,” Ferrari told WFTS Action News. “The next one wasn’t correct and the next one wasn’t correct.”

Ferrari had paid Verizon a little more than $100 a month, but Frontier sent a bill for more than $340. Calls to customer service brought broken promises the company will fix Ferrari’s bill, but the overcharges kept on coming. Subsequent calls to Frontier have accomplished nothing, and attempts to speak with a supervisor were denied.

Customers who decide to cancel their Frontier service and change providers are not out of the woods yet either. Canceling is what 79-year old Dennis Klocek from Palm Springs, Calif. tried to do, leaving him owed $127.62 for dropping his Frontier phone, TV, and internet service. Frontier claims it refunds customers not with a check, but a prepaid debit card, which the company promised to mail to his home address. It never arrived.

When Klocek called Frontier about the missing card, the company refused to reimburse him, claiming the card had been sent and was almost entirely depleted by someone who used it at several convenience stores and fast food restaurants in nearby Cathedral City. As far as Frontier was concerned, once the card was mailed, the matter was out of their hands and responsibility. Klocek is upset Frontier sent his refund in the form of a debit card, which he never authorized and obviously lacked the security features a refund check would have given him.

“These people can’t get away with this,” Klockek told KESQ-TV. “What’s going on? How many other people are getting screwed like this? I don’t like this and I am going to get to the bottom of it. I feel empty. I feel like I can’t trust anybody in big business, meaning ‘AKA’ Frontier.”

Frontier also refused Klockek’s request to speak to a supervisor, leaving him at a dead end. He took his complaint to the Palm Springs television station instead, which seems to potentially bring Frontier around.

“We empathize with our former customer and are actively helping him work with the card issuer to implement a fraud investigation, resolve the matter and receive the refund,” wrote Frontier representative Javier Mendoza.

WFTS-TV in Tampa reports multiple Florida customers are having billing problems with Frontier Communications. (1:38)

Back in Tampa, Frontier customer Christina Herrman said she’s been dealing with overcharges by Frontier Communications for years.

“Ever since Frontier took over, our bill has gotten exceedingly more each month, now up to $260,” she posted on a thread talking about the issue on Facebook. “Even charging us for a 2nd cable box/DVR for the past year that we never had.”

Requesting a supervisor can lead to punishing hold times.

“I wait on hold for 20 minutes to get one on the phone, to spend another hour and they can’t help me,” she posted. “Hours upon hours wasted trying to deal with them.”

She eventually surrendered and now just pays whatever amount Frontier bills her.

In Dallas, Tex., Beth Smith Powell also took to Frontier’s Facebook page to complain she spent almost 40 hours on the phone with Frontier representatives about their bait and switch promotions.

“I had a sales rep come to my home and give me a price on TV/internet/phone for two years,” Powell wrote. “I asked her several time was this price good for the full two years, she said yes.”

When the first bill arrived, it was nearly $500, leaving Powell aghast. After two hours with Frontier’s customer service, she was promised the bill would be adjusted. It wasn’t adjusted much because when the next bill arrived, it was over $400, forcing her to spend another two hours working with Frontier to straighten that bill out. In the meantime, she was threatened with service interruption and a collection agency if her original bill was not paid in full.

Just a few months later, Powell’s bill suddenly increased $40 a month and nobody could initially explain why.

“Come to find out my two-year CONTRACT was BS — it was only a six-month discount,” Powell wrote. “I have the paperwork but […] Frontier will not honor this contract.”

It appeared Frontier walked away from the commitments their third-party door-to-door sales agents made promising 24 months of savings by only delivering six, after the billing errors were corrected.

“Shame on Frontier for being dishonest and not honoring your written sales rep contract,” Powell complains. “I’ve spent about 40 hours on the phone and chat trying to get help and no one will honor your advertised rate!”

Alan Borden, a Tampa consumer protection attorney with Debt Relief Legal Group, told WFTS Frontier’s bills are very long and hard to understand.

“They make it as convoluted as possible but theoretically, they can sneak in these overcharges where you won’t notice, or you’ll just give up,” Borden said.

Which is exactly what many customers do. Frontier has earned an “F” rating from the Better Business Bureau and has collected more than 9,400 customer complaints in the last few years.