********** activities ,Incorrect Billing and Poor service

I have this account for years on 6months interest free however ever since the change which was never communicated how my account is handled has been shocking, the account was settled however December 2020 i decided to use it a bit little did i know that it will be the start of ********** activities and they have added some policies i was to told about , i have been paying but debt does'nt reduce only to find out that i have those policies added , was advised that they will close them and refund me instant i still get statement that i must pay while i have already settled debt based on purchases made , i have been sending emails, going to the store and calling still no assistance , am sick and tired of this poor service this delay in sorting this matter will affect my credit score as i cannot continue paying when i do not owe all i want is my refund and my account rectified