A French woman spent hours on the phone last month with telecom customer service reps, trying to convince them her $15-quadrillion phone bill was a mistake, Toronto Sun reports.

Solenne San Jose, from Pessac, in the Bordeaux region of France, terminated her contract with Bouygues Telecom in September, reports the French news service Sud Ouest. When she got her bill on Sept 28 with the cancellation fee, she said she "almost had a heart attack."

She was told 11,721,000,000,000,000 euros — which is about $15 quadrillion, or nearly 6,000 times more than her country's GDP — would automatically be withdrawn from her account.

"It was so many zeroes I couldn't even figure out how much it was," she told the newspaper.

Eventually, Bouygues admitted the amount was a mistake, but not before many frustrating hours of San Jose pleading and arguing with customer service reps on the phone.

"When I explained it was a mistake, they'd say it was all automatically calculated and withdrawals would begin shortly," she said. "The first time I called, I spent at least 45 minutes on the phone with one operator. He replied, 'It's automatic. There's nothing I can do.'"

One operator told her she could pay in instalments — 11,721 million of them.

"How many thousands of generations would it take to pay this bill?" she said.

Finally, they admitted the error. Her actual bill was $149.