Credit Card Closure

I called Discovery Card to cancel my credit card and close the account on 19 June 2019, I was informed that someone from accounts will call me in 3-5 working days to process my request. I did not receive a call back.I called again on 26 June 2019 and told that they have been trying to contact me but no success, the agent informed me that she can email me the Account closure form then once completed my account closure will be processed. Today I call and I am being told that it will take 5 working days to refund the miles account and then another 5 working days to credit to my bank account. My account has been paid up for the past 2+ months but I am now struggling to close the account. I don't understand how it takes half a month to close the account when I don't owe anything on this account. This is unacceptable