Very bad service

I terminated my membership with medscheme in October 2019 and was told to call back after 6 months to check if I am due for refund which I did in May and I was advised that they tried to reimburse me but the payment keep coming back and it was because I changed the banking detail. I was told to send thru the bank statement with the id copy with I did, adter 3 weeks I checked with them as I didn't get the refund, I spoke to an agent who advised me that they didn't get the bank statement, I was very much surprised cause both documents were on one email which I then forward to them again, none of them is attending to my request, I checked their complains department and was not assisted, I forwarded the request to the fund manager 2 times which I never got any feedback. I must really say its a very bad service and they don't even care about the customers rights and needs. They are only nice when you sign in once they win you as a client even management don't care about the service offered to you.