Closing revolving loan and paid up letter delaying

I be been annoyed about standard bank to settle their loan several times and did as their request and it in full,but now am having a problem when it comes to them to close my account instead they transferred my call to the line that nobody is picking it up more than an hour with no what they want they only want to benefit accumulation of interest on my account for their loan not to be removed we also have other things to sort out with paid up letter