Mulichoice takink double payment out my account

I bought a explora from dstv and when I received it I let a friend connected it and phoned them to cancel my hd pvr.now after two months and more than 5 phone calls to them they still didn't cancel my pvr,but they charged me for the last two months for the explora subscription R850.00 and for the pvr subscription R790.00.now after a few phone calls and three letters to them they still didn't pay back my pvr subscription fee. I also have problems with the explore from their side,awile ago I couldn't whatch programs that I taped and had to phone them several times before they fixed it.a few weeks ago I coudnt use the app on my phone to record programs and after more than 3 phonecalls they fixed it.