ACCOUNT NO *** - INTEREST CHARGED

I received my March'15 with a R26 annual service fee billed. I phoned customer service on either the 7th or 8th April'15 and explained that I didn't agree to this charge. The lady that assisted explained agreed to reverse the charge. A week later I received an sms stating my account was in arrears. Again I phoned customer services and I was told to ignore the sms. The following day I received a phone call to enquire when I will be paying the amount in arrears. I immediately requested to speak to a supervisor. According to the supervision the R26 charge was only reversed the previous day. I asked why as I phoned more than a week ago. I requested in writing an explanation why it's taken more than a week to reverse this charge as well as confirmation that NO interest was charged to my account and that the R26 was reversed. Later the same day a manager phoned me regarding this matter and again I requested confirmation. I have received my April'15 statement with a R2.90 interest charge. I e-mailed and explained AGAIN and received an answer that this was due to late payment on my side. Please note that I will be settling the balance in FULL and closing this account as per my last mail