Disgruntled customer

On January 13th, I went through the process to close my credit card account with the help of a call centre agent. She was extremely helpful. My account is still not closed and I have now received a 3rd statement with service fees (that I do not owe). I have phoned several times and each time, I spoke with extremely pleasant and empathetic call agents. They can see I closed the account from my side but don't know why it remains open at the bank. The best they have been able to do is escalate. How often though, does this loop have to continue. The amount of time it has taken me to write and telephone has now totalled several hours. I can't understand why a bank that considers itself prestigious, cannot get something as simple as this right. Either they employ *********** people or their systems are not up to the job.