Payment not allocated

I have paid my finchoice account through them and the they gave me a paid up letter. Later I received calls from a difference company collecting for the same finchoice account, as this was confusing to me I then bought a credit report only to find out that the same finchoice account still exists with the same balance. I contacted them for clarity a gentleman named Sifiso promised to follow up on this, but he never contacted me again. I made the payment on the 21st April 2021.What is also confusing on ths matter is that the account number for the finchoice account I paid to them is not on my credit report, the only one that appears is the one with the outstanding balance. I want to to know what have I paid, where did my money go. When I first spoke with them a lady named Mpho was assisting me and I asked why was my balance difference from the one I known, I asked if she was sure that no one else will call me again for the same account. She assured me now I getting call again for the same account.