The man from Fukuoka, Japan, said his cell phone was stolen on December 29 while riding the Barcelona, Spain, subway.
The man, identified by his Twitter name, Omomo, said that he had notified his service provider about the theft within 15 hours, UPI reported.
However, after he returned to Japan, his monthly bill came to 994,919 Japanese yen (USD 9,800), and majority of it run up the day after the loss of the phone.
"I feel like my head's sprung a leak," he was quoted as saying.
"I talked to the staff at SoftBank shop and the police. I was told that if the thief is caught I won't have to pay the fees, but the chance of that happening is pretty slim," Omomo tweeted.