BILLING ********LY

I paid RCS account in 2015 and after i made a payment i've never received any communication from RCS and this year january i received a call from blake advising me that i'm owing RCS i asked them to sent me payment history which they never did and last month i received another call from collection agencies telling me the same story. i called RCS and i went to the store and paid all the amount that i was informed that i owed and now i want to close the account i've been refer to different people which now there are telling me that i need to pay the collection cost. What collection fee are there talking about because they only called me only once and i decided to go and pay.