Cartrack - Accounts Department - Worst ever

Received the worst service ever from Cartrack. I bought a car from my sister and on 29.06.2022 I paid the Change of Ownership fee of R350.00 - but they keep sending messages that my sister's account is in arrears and that they did not receive the payment. Rude staff, Nthabiseng just told my sister that it is not paid - done - no investigate or "I will look into it" since we did send them the proof of payment - just a " no it is not paid". Sent the Proof of payment again, but still they send messages that her account is in arrears.... as per the Cartrack statement, a MANUAL reversal was done on their side from her account of the amount R350.00 on 30.09.2022. They claim is went back to my bank account - not. I sent them my transaction history, then my bank statement, then confirmation from the bank that there was no reversal of that EFT payment... but still they will just respond with a "no it is not paid", "it was reversed", "check your bank". They do not provide any usefull feedback and they just pass the buck without sorting our issue. I asked, more than once, I want PROOF that they have paid it back to my bank account, but they just ignore that statement and they do not provide any info at all.