Citibank Pathetic service

Barnard Today, 15 Jan 2019 and still no sign of any payments made to me as the member for claims submitted to De is about 4 months back. Apparently Citibank is still cancelling a cheque from the 4th of January 2019, that was never posted in the first place. So it takes Citibank 11 days to cancel a cheque. The best Denis can do is phoning me to tell me Citibank still did not come back to them.... I guess thats Citibank for you. Is cancelling a cheque by a bank really such a lengthy difficult process?