Statement incorrect How?

Hi, my mr price account was handed to nimble collections... On the 19th of May 2020 i asked them to send me the statement i need to settle my account. I was provided with a statement wich showed the amount of R3004. 72 then i made a payment of R1500. 00 and ive sent them a proof of payment to Regina one of the consultants. She then advised that the amount that im owing is R3303. 49 i then asked how is that possible if they have sent me the statement on the 19th of may and they update their statements on the 3rd of each month she did not have any further explanation to my question. I then phoned their offices i spoke to a coloured lady and when i came to ask how come is the statement incorrect that was sent to me. She then advised that she has already closed the file and she said bye and she put the phone down... How do i trust this people because from what i can see from their statement the account statement gets updated every month on the 3rd so how come am i paying something that does not reflect on the statement provided and on their email they have provided me with the account number that does not refelect with the one i got from clear score and creditcheck.. I am so not happy with the customer service i got from them

I ask for your urgent assistance in this matter

Regards