Loan not closed on request

Bad service and wrong billing: I closed my loan account in March but I recieve sms's threatening to take me to authorities because they have an outstanding amount coming from service interest and insurance. I get to the bank they acknowledge that it was to be closed but don't know what happened while waiting to be further consulted they leave me they saying they are done as I stand by the desk alone. I follow asking if they r sure it will be closed the lady says that she took my number so clearly she will n refuses to give me a number I can contact them to confirm auctioning. When I leave the bank she comes again running after me to say I must sign a template with no info on it and gives me a copy as id asked. What will I do with an empty template? Why is standard bank so poor at giving the smallest service. Do they no longer need or want us as clients. I really regret having them as my provider and trust to be switching banks by month end