False Statements

Why get a statement and pay and then next month being charge for collection cost and arrear amount ? After sending an email and just being passed on I phoned Claudia and then the excuses that we paid late ,the statements being send out without all figures being proses. But we have done an immediate payment on the 30/09/2015 ,but due date 01/10/2015.If you're in the rear they will charge you interest on interest and after big argument with her I wanted to be transferred to her manager Flaurance .I also told Claudia that I`m going to complain on helloPeter , Bank Ombudsman and other social mediums and her reply ....I`m free to do as I pleased. Please get the phone recording and confirm this .As always the manager is busy and will call me back and being persistent to speak to her and being put on to hold all off a sudden the rear amount will be reversed and an emailed send to us and still waiting for it. I don`t just want an email and want the statement to be rectified and the correct figures..