The bank that won’t help me to cancel my credit card.

I have been trying to cancel my Discovery credit card since last year. Every time I phone them they say they will send me a cancellation form. Then Discovery bank took over the administration so I tried again because in the meanwhile bank fees pile up and discovery miles yearly fee so all extra fees I need to pay now because of bad administration. Then I phoned them on Monday again made it clear I want to cancel. Was promised someone will phone me within 2 days to cancel my card. Received a call on Wednesday because according to them I requested to open another card??? Now on Thursday evening I receive a e-mail that I must send them an e-mail giving reasons why I want to cancel my card after months of phone calls and after they promised they will phone me to cancel now I need to confirm again??? This is ridiculous!!!