Hamid Saberi, who banks with Lloyds TSB, logged into his online banking account on Saturday to discover the words "You A F****** Debtor B******" added to his current account.
The shocked 41-year-old immediately contacted the bank and asked for the words to be removed – but four days later nothing had been done.
Mr Saberi, from Gorbals, said: "I was just logging in to check my bank balance and I saw this written above my current account. I couldn't believe it.
"I thought the site had been hacked but I checked my money and nothing was missing. Then I began to think the words had been written about me personally and I found that very upsetting. I just wanted them gone."
Mr Saberi, a chemist, called the bank's online banking helpline and asked for the words to be taken down. He was told that the call handler would speak to a supervisor and have the words removed.
But on Sunday the extremely offensive message was still present.
Mr Saberi, who has been with Lloyds TSB since 2000, added: "I was really upset about it. My wife had seen it too and this is not the kind of language we use in our home. It made me feel very, very low."
On Monday Mr Saberi, originally from Iran, phoned the bank again and was again told something would be done.
However, the message was still there so he contacted his local police office. He was then told the bank was investigating the comment.
But the message was still present on his account on Tuesday evening – four days after it first appeared.
Mr Saberi said: "It's just not acceptable. I have had no response at all from the bank and that is why I have taken the step of coming to the Evening Times as I didn't know who else could help.
"The language is really terrible. This is verbal assault."
The message was finally removed yesterday afternoon – after the Evening Times contacted Lloyds TSB.
A spokeswoman for the bank said: "We are very sorry to hear of Mr Saberi's experience.
"Our investigation has indicated that his account was accessed by an unknown third party. Our fraud detection systems recognised the threat, meaning that no money was able to be withdrawn.
"However, they did manage to make changes to the account settings. We will be passing the information on to our police liaison department who will co-operate fully with any police investigation into the incident."