It has to be the best credit card scam ever - and it worked.

When Dmitry Argarkov was sent a letter offering him a credit card, he found the rates not to his liking.

Mr Argarkov's version of the contract contained a zero per cent interest rate, no fees and no credit limit. Every time the bank failed to comply with the rules, he would fine them 3 million roubles. Credit:Karl Hilzinger

But he didn't throw the contract away or shred it. Instead, the 42-year-old from Voronezh, Russia, scanned it into his computer, altered the terms and sent it back to Tinkoff Credit Systems.

Mr Argarkov's version of the contract contained a zero per cent interest rate, no fees and no credit limit. Every time the bank failed to comply with the rules, he would fine them 3 million roubles ($A100,000). If Tinkoff tried to cancel the contract, it would have to pay him 6 million roubles.