payment

I'm not happy with markam i paid my account on the 1 may 2020 but to find out they gave me wrong reference. I called to find out how to fix it they said i must submitt proof of payment. I then sent it to them on the 7th may 2020 till now they did not responded to me. i call several times but it seems no one knows what to do they sent me from pillar to post. Im really not happy because is affecting my credit scoring.My ID ***