Dstv Portal adding double subscriptions to my account.

I have subscribed to DSTV's Premium Streaming Package on the website (My DSTV) and paid for it with my Credit Card. The payment went through successfully. However, the next day when I went onto the portal it showed that I am still owing. Upon thorough investigation, I discovered that upon subscription they added by mistake two subscriptions to my account wanting to bill me twice. I only subscribed once. Why would I have subscribed twice? The sad thing is that I can only stream one device at a time so it was not even that I could reap the benefit. This is extremely unfair and I demand that my account be credited as this was a glitch in the system. Furthermore, I paid for my subscription with my credit card, why would I pay for the one and subscribe again and not pay? Please assist urgently.