Still awaiting credit on decoder insurance

I phoned DSTV decoder care twice already regarding the double deduction for my 2 decoders for the past 2 months (September and October). I even went as far as logging a complaint on their self service website yesterday when I checked my account and saw that my query has not been attended to because when I phoned the last time I spent almost half an hour with the call centre agent and still my query has not been resolved. They promised me that my account would be credited but its been 2 weeks now since I logged the 1st initial call and I am still awaiting the credit. I already paid my subscription for the upcoming month where I paid the outstanding balance due on the account less the credit expected. I will not be suprised and I am actually afraid that they will disconnect my service due to the outstanding balance which is no fault on my part, according to me my account is up to date with them. Please fix my account.