Wrong amount on paid up loan

I had a loan with African bank went on debt review but settled the loan myself got a paid up letter but now 9 months later after settling it im told it is in arrears been contacting the debt counselling department im always told it department is sorting the matter they have been sorting it it since may to date it has affected my credit score I ask for the settlement amount they can’t send it bad service I got from African bank even their reference number I got is not of assistance as they can see what’s happening regarding it