Debit order struggles

I've been struggling with this company for a few months now.

I have the catrack devit order on my fnb debit order mandates.It doesn't go off end of month.then cartrack keeps harassing me wih calls and whatsapp messages.i then pay them using their paym8 site,which doesn't send proof of payment.i then send them a screenshot that i paid.Then they want a detailed proof of payment which i can't send.Then they keep sending me whatsapps saying i need to pay.