Unhappy customer

Am really disappointed by how my matter is(was) handled by the Branch Manager of FNB in Sandton, i went there twice and the first time this happened. I bought a car last year April and my car was financed by WesBank, fast forward to September 2017 i got a job at another bank and that bank toke over my car finance and paid off Wesbank. So this whole process happened before end of September and i called Wesbank to inform them about this and told them the last installment was not going to go through on the date we agreed on before because i was going to get paid later that month and I called Wesbank to alert them about it and the consultant i spoke to said that he will change my payment date and i should pay atleast before the 7th of October and the consultant advised me that i can pay it via EFT or Internet banking, of which i made R3000 deposit last year 1st of October via ATM and i was never told to send proof of payment. Now 4 months later i get an sms this month on the 1st of February 2018 i got an sms from Wesbank in regards of payment i made on my previous account with them apparently which was Closed the time i made the payment of which no one told me about it even the consultant I called before didn't see that. So i called Wesbank back to explain that proof of payment i do not have it anymore and they insisted that i get that proof of payment slip. then i went to the same branch i did the deposit at and i spike to the consultant and he explained to him my issue and asked him to print backup deposit slip and he told me i impossible to get atm deposit slip that is far back with months. He then printed me transaction history and told me to send it to Wesbank. I sent it and they got back to me and told me they cant accept transaction they need payment deposit slip. I then went back again to the branch after 6 days and I asked for Branch manager, i then explained to the Branch Manager my issue and he then told me that printing the archived ATM deposit slip he might be able to help me with is however his reluctant to do that especially if is not their fault as a bank, of which surprised me however he said he will see what he can do and he toke my details and gave me his email address and told me to send him an email Monday to check if he managed to get me the the deposit slip cause i really need it to get my money back . Fast forward to the 21st of February is been two weeks since i sent him two emails and i haven't received any feedback from him. I then tried calling the branch and only to find out that calls do not go straight to the branch and and he the consultant i spoke to told me to give him my details and what is in regards with what and gave him my contact details.Can someone intervene because this is not acceptable especially knowing that this whole this is doable.