ABN AMRO Credit Card — Threatening to spoil my credit history and adding charges for their delays

HI,
I am holding ABN Amro card. Every month I used to pay bill by submitting cheques by dropping it in ABN Amro ATM. Due to ineffeciency of their cheque collection department they produce the cheque to my bank (ICICI) in 10 - 12 and I end up paying extra charges that makes aroung 1000/- including late fee, service charges and interest on billed amount.

Finally I decided to close this card by paying all billed and unbilled amount by dropping cheque in ATM and informed Bank about closure of card and issuing me NOC. After paying all my dues I never make any transaction. This time they again took time and submitted the bill after generating next month bill of service charge and all other charges.

Since then I am following up with bank to reverse the unecessaray charges and issue me NOC but always my request is getting rejected and collection depertment are giving me thretening calls.

Please help me.

Thanks,
Ashish Srivastava