It is one of the bugbears of modern life, the distant voice down a crackly line from a call centre somewhere in southern India.

But George Bates, 23, has more reason to complain than most. Disgruntled by the rejection of an extension of his overdraft because he had only just increased his limit, he gave a less than enthusiastic response in a post-call customer satisfaction survey.

The next day he found himself locked out of his account with the Abbey bank, his debit card was swallowed by a cash machine, his overdraft facility had been withdrawn and he was down on bank records as a 33-year-old Ugandan divorcée.

When he complained an Abbey manager revealed that someone had changed his account details and as a result he had to pay £60 in penalties because six direct debits went unpaid.

The Abbey has now apologised to Mr Bates, who has never been married, let alone divorced, repaid the £60 charges and offered him £200 compensation for his “inconvenience”.

The bank says that it is investigating the complaint that his account was sabotaged by a call-centre employee in India. Mr Bates originally telephoned the Abbey's call centre to arrange an extra overdraft to cover a couple of unexpected payments. When he called back later to ask for a little more than originally agreed he was told that the bank had a policy of not extending an overdraft twice in one day.

Mr Bates says the adviser had an Indian accent and the line was so bad that he could hardly understand what he was saying. He claims that the man was “arrogant and rude” and is convinced that he changed his account details out of spite.

He said: “The phone operator has obviously seen that I've given him bad feedback and decided to change all my details in revenge. I rang up but I couldn't understand a word of what he was saying. He was really unhelpful but he had the cheek to pester me to give him a good rating after the call.

“When I heard my details had been changed I was terrified that my account had been emptied and I'd never have my money back. His spiteful actions have caused me a massive inconvenience and I've changed banks because I'm scared he could still access my account.”

Mr Bates claims that the adviser pestered him to give maximum scores of seven in an eight-question automated survey that customers take after a call. He answered the questions with ones and twos, the lowest scores, because he felt that the man had been unhelpful. When he rang the next day to again try to extend his overdraft he was unable to access his account. He visited the Abbey branch in Broadmead, Bristol, where a manager informed him that his account details had been altered.

The Abbey later agreed to pay the penalty charges and offered compensation, which he has refused.

He said: “I am not happy with the service and the fact that the call centre Abbey uses is in India. They offered me £200 compensation but that's not a good apology to me. I've been forced to take lots of time off work which has costs me several day's wages and the stress of it all is really frustrating.”