Call centre team leader not responding to query

I had a card with Game stores which was paid up in June 2015 , in July 2015 I received a closure letter from RCS confirming account is closed but for the past months I'm still receiving statements showing that it is open , at some point it was in arrears and the recent shows collection fees. I have called their call centre on numerous times and even sent an email to a team leader Gailin Bartie who did not respond. Yesterday I called again and spoke to Ayisha Issacs who promised that this Gialin will call me back. I'm still waiting and when I call today a Xolisa tells me he is busy with interviews. I'm worried that what is see on this statement might have caused a bad record on my ITC score. I want to know how come I have a letter of closure but the account is still open and why are team leaders too busy to talk to customers.