RCS WONT ISSUE PAID UP LETTER

RCS is so quick to respond when you ask for a settlement amount but i have paid up my account on the 28th June already and send numerous emails for a paid up letter and they refuse to give it to me. My account is also in credit. I want to buy a house and need this to be updated at the bureaus. i called in now and asked to speak to a supervisor and was left holding for almost 10 mins until my airtime was up. This is not fair and totally unacceptable.