FNB.........THIS IS HOW YOU CAN HELP!!! GIVE BACK MY MONEY

I had my car finance with Wesbank which i have recently settled in Jan2021. I was given a settlement amount which i had paid in full. The amount is reflecting on the last statement that i had received from Wesbank.....My account is now in a credit balance, I had contacted Wesbank for a refund. My last mail from the which is now the 4th time trying to sort out says that i need to send them proof of payment of the settlement amount plus the last 3 installments proof, WHY??? these amounts are allocated to my statement already....bottom line Wesbank owes me money which is clearly reflecting on the statement they sent to me, but they are now asking for proof of payment......My question is how did they allocate my payments to the statement if they are not sure that i have paid this.......Also it is now the 3rd time that i hasve requested all logbooks & documents to be sent to me....NOTHING HAS BEEN DONE......I want my money back & my logbook for the vehicle