Collections - Complaint

I have made my car installment payment on the 2 February 2018. Wesbank collections has been harassing me with calls claiming that i am owing installments. They asked for proof of payments which i sent and they still called me asking for the same thing. When i explain that i have sent, they refuse to listen.

They still keep calling me and have sent me a statement with interests added plus and amount of R7000 as pending payment.