Barclays Credit Card
Non-verification of cheques written before submitting to the bank

I have paid my credit card bill through cheque in which I made an error. I forgot to put my signature on it. This credit card department did not verify my cheque properly and it submitted it the appropriate bank. When I enquired the bank on this they say that the cheque got bounced. Due to the negligence of this credit card department I have been charged heavily from both sides (i.e., the bank as well as the credit card bill). Is it not the responsibility of them to check these things before presenting the cheque? And they wrongly term this to be a cheque bounce. A cheque gets bounced only if there is insufficient amount in the account referred by the cheque. When I came to know this I called the customer care about this. They say irresponsibly that not all the cheques are verified by them before presenting them