Failure to close account settled

Good day, In Dec'15 I phoned for a settlement amount on my Builders Card - which they provided, which I paid. After that I sent emails with the proof of payment and requested the account to be closed. This didn't happen. I phoned again in Jan when I got a statement with an amount outstanding (running up interest & costs). The consultant said she will escalate it. No response. 5 Feb I called again and after a difficult struggle with the consultant, I spoke to her supervisor Fikile Sikweza. After I have used up all my cellphone minutes waiting for him to look into the matter, he said they provided me with the wrong settlement amount - which isn't my problem. He said they will write off int and fees and that there is an amount outstanding that I must pay. He will send me a letter in this regard. He didn't. 9 Feb I phoned again, and then he sent the letter saying I must pay by 12 Feb and advise him when I did pay. Which I did on 12 Feb. No reaction from his side on my email from 12 Feb, nor on my follow up emails from 18 Feb and 19 Feb. This is as bad as the service in The Builders Store - RCS should take action against such poor service and reimburse me for my cell costs.