Paying for a service not reveived.

I was part of a free Vitality HealthyWeight trail with Discovery. I then completed the 6month program, and was offered 2 options to continue - I opted for the maintenance plan @ R99 per month. I updated my details on the 3rd of Aug and have not heard anything. I actually forgot about this, until the payment was charged to my credit card on the 21st of August. I logged a query on the same day with reference number ***. No feedback received what so ever. This is really not acceptable - I demand that my membership be cancelled and that my money is refunded.