A man says he has been wrongly billed £19,000 by Orange for using the internet on his iPhone 4S.
Chris Bovis, 26, from Tilbury in Essex, said his phone was cut off after data was sent from his handset without his instruction over a two-month period.
He said Orange had unsuccessfully tried to take the money from his bank. His bill is normally "about £43 a month".
Orange said it had received confirmation that it was a problem with the handset and was changing the bill.
"We would like to sincerely apologise to Mr Bovis for any distress caused by receiving this unusually high phone bill," a spokesperson said.
The £19,000 owed to Orange was for data usage for October and November.
Mr Bovis said a member of staff at Apple's store at Lakeside Shopping Centre confirmed that it was due to a problem with the phone, and gave him a replacement handset.
Speaking before Orange said it would cancel the bill, Mr Bovis said: "I've got the proof the phone is at fault but Orange are not interested.
"They say I should take it up with Apple to try and get the money from them for the inconvenience."
Mr Bovis, who works as a builder but said he lost his job shortly before Christmas, said his festive season was "ruined" by the ordeal.
"Over Christmas I didn't know if the bailiffs were going to turn up and take everything," he said.
He said he was worried the row could have a knock-on effect on his credit rating.
"I'm not after compensation, I just want them to cancel the contract so I can go with another provider," he said.
"Their service is abysmal and I've lost too much sleep worrying about it."
Apple is yet to comment.