No success in allocating payment made on Jet account

Since Jet moved from Edcon to RCS it has been giving me Grey hairs. Firstly I tried shopping and they told me I had to change my card as their systems have changed. I changed the card. Made a payment using the new card 26 September 2020 and got a slip. They kept sending me threatening letters telling me I'm in arrears and constantly calling me. I send proof of payment to their payments email and I keep getting a dumb response telling me to send electronic payment details. Hello, I sent my bank statement and the slip showing payment made. I apid in store using the point of sale machine. The slip has my account details and shows the balance before and after payment and amount paid. They still can't help me. From 23 October 2020 I've been trying to pay October premium at different branches but none of them were able to help me but was told again my card is not working and had to change it again. Till today I'm busy sending emails to all the different email addresses in getting from their threatening letters. I'm going to end up closing the account if this is not fixed as they are ruining my credit record because of their faults and numerous changes. Can someone who knows what they are doing help me. I'm up to my neck with Jet.