Overcharge

I've been charged R139 extra this month....I'm not sure what or why this is!I have not been advised of any price increase. I sent a msg on chat live n got no response. I just read an article from My broadband that customers were mistakenly charged for discovery +... I have never watched this channel I don't even know the channel number. Dstv please refund me the full amount immediately. I'm tired of your poor customer service