Very bad service and unprofessional

I paid my outstanding balance on the 1st of March and they told me I would receive a clearance letter but I didn't receive, I've been calling them almost everyday for it but they just redirect me to another branch where they don't answer or they just hang up on me . Then recently I was told I had an outstanding balance which I didn't understand because I paid it up in March bu6i paid it including the clearance letter amount and still haven't received my letter, they just put me on hold for 30 minutes or longer till I hang up or they hang up. this company is really unprofessional, wish I knew where to report them because this is not it