Accounts department

My experience with this academy is terrible! After numerous emails and a phone call their accounts department have still not gotten back to me regarding my outstanding account. They now claim not to give my sons certificate due to the account been in arrears. I am trying to sort the account out with them but the lady in their accounts department has no clue and told me she would get the financial manager to call me. I am still waiting on that call. Apparently with them they don’t give you an invoice to pay and put interest on your account to sum up to the amount! When I asked for an invoice I was told you don’t get one and I am the first person to complain about this. I myself am an accountant and can’t understand how they can run a business like this!