Imagine returning from an overseas work trip and being greeted with a $191,000 phone bill.

Kim Beveridge's first reaction after counting the zeros wasn't one of horror or event shock, but amazement. He couldn't fathom how a mobile phone service could rack up that sort of a bill.

He's fought the charge since he received the bill in 2014 — arguing he shouldn't be responsible for the staggering fee (which included more than $17,000 in GST).

It took until last month, but the Supreme Court of Victoria has now upheld a decision that Mr Beveridge shouldn't be responsible for the charges.

So how did it happen?

4,484 calls in 20 hours?

By 2014 standards, Mr Beveridge seemingly did everything right before travelling from Melbourne to Barcelona.

A senior executive at a software company, Mr Beveridge contacted his mobile phone service provider TeleChoice, a reseller of the Telstra mobile service, and enquired about international roaming.

He paid a bond to TeleChoice for the roaming service, which included a daily capped charge amount, and activated it on the way to the airport.

Ironically, Mr Beveridge was attending a mobile phone and payments conference in the Catalan city.

Then his phone was pickpocketed around 5:30am after a late night out with colleagues.

He called Australia the next day — roughly 20 hours later — and reported the theft.

"They had just notified me that they detected some suspect calls and suspect behaviour on my account, so they had blocked the account at that point," Mr Beveridge said.

"I got home and a week or so after, I had a $191,000 bill land in my inbox."

TeleChoice initially pursued Kim Beveridge for the full amount of the phone bill. ( Supplied: Kim Beveridge )

The bill documented pages and pages of calls that were made during that 20 hours.

In total, there were 4,484 calls amounting to 1,161 hours of conversation, and thousands more text messages.

The numbers didn't add up. Mr Beveridge couldn't understand what he was looking at.

It transpired he had been the victim of a sophisticated scam.

"What seems to have happened is the scammers have removed the SIM card from my phone and put it in another phone and activated call forwarding to a number in Latvia," said Mr Beveridge.

"Then they've set up some sort of service so many calls could be made at the same time."

TeleChoice knock the price down... to $34,000

Mr Beveridge contacted TeleChoice, who verified the bill and insisted he would have to pay the full amount.

He refused, and contacted the Telecommunications Industry Ombudsman. They said they could not assist with matters over $50,000, and advised Mr Beveridge to contact a lawyer.

TeleChoice pursued Mr Beveridge for the full amount, and the case wound up in the County Court of Victoria.

Nine months later, after the judge threatened to rule their pursuit of the $191,000 charge as unconscionable, TeleChoice reduced their claim to $34,000.

Mr Beveridge's legal team's defence centred on the terms of his contract with TeleChoice, challenging their entitlement to charge for call-forwarding on international roaming services.

In 2016, the County Court found in favour of Mr Beveridge, dismissing TeleChoice's claim and ordering them to pay court costs.

Dissatisfied with the outcome, the telco took the case to the Victorian Supreme Court, dragging the legal battle on for another a year.

Finally last month, the Supreme Court of Victoria upheld the decision.

Kim Beveridge said he's hoping to move on and put the matter behind him now. ( ABC RN: Jeremy Story Carter )

"It's been a long battle," said Mr Beveridge.

"It's been a pretty stressful time. We're just trying to put the case behind us."

Due to changes in the way telcos offer international mobile services, Mr Beveridge's case is thankfully rare.

The Telecommunications Customer Ombudsman calls the situation "very unusual", with international roaming now accounting for less than 1 per cent of complaints.

Mr Beveridge considers himself lucky that he had the means to defend himself in the courts. But he's changed the way he uses his phone while overseas.

"All of my family has switched to a prepaid service. You know what you're up for and it'll be cut off after your balance is reached," he said.

"That's it."

The Law Report contacted TeleChoice for comment but they declined, saying they are still considering their legal position.