Useless home loan call centre

I've phoned nedbank multiple times with regards my home loan and their nedrevolve services, but it's like their staff don't know the product or they don't want to understand what I am asking. I've been paying in to my home loan account but the extra money doesn't seem to 've available to me. And they also can't tell me what the arrears is on my account as I have never missed a payment and I'm paying in extra