When Chris Bovis, a 26-year-old builder from Tilbury in Essex, was cut off by Orange without warning, he thought a mistake must have been made.
But when the iPhone user contacted Orange and was told he owed close to £19,000, his surprise soon turned to shock and dismay.
Orange cut off Bovis' services when its attempts to take the huge bill payments from his account were blocked.
When he called to find out what was going on, Bovis was told he had racked up a bill of £8,900 down to unusually high internet usage.
He also told the Daily Mail newspaper that the Orange adviser he was talking to warned him his next bill was due to be another £10,000.
Bovis said: "My first reaction was to laugh, but it stopped being funny when I realised they were totally serious."
Investigations indicate that the sky-high charges were caused by a fault with his iPhone, which meant it started sending and receiving large amounts of internet data in error.
But despite staff at the Apple store agreeing that the phone was faulty, Orange still plans to claim £300 from Bovis unless Apple confirms the problem.
Orange said: "We are happy to reduce the bill to zero as soon as we have received confirmation of the fault from his manufacturer."
Whether Apple will take responsibility for the problem with Bovis' iPhone remains to be seen. But he is far from the only Briton to receive a terrifyingly high mobile phone bill.
The main difference is that almost all the eye-watering bills that have hit the headlines in the past have involved consumers using their phones while overseas.
Back in March 2008, for example, I wrote a piece for The Sunday Times about a City executive who received an £11,000 Vodafone bill after a download of four episodes of the sitcom Friends continued automatically while he was working away in Germany.
And more recently, the Huffington Post reported that Devon-based Anne Roberts was hit with a £27,000 Orange bill after buying a £20 pay-as-you-go phone while on holiday in South Wales.
Like Bovis, her shock bill was caused by a technical glitch, this time on the part of the mobile operator, which charged her account 792 times.