Dstv constant bad service

dstv keeps at it, they keep giving us bad service just when you think they have stopped they start again, they are charging me R754 instead of R684 I topped up my dstv account of the amount R70 on the 20 August and rented 2 movies then topped up again in September R70 and rented 2 movies but the top up in September didn't go through my account but we managed to watch movies so I naturally assumed my bill would be R684 but no I'm charged R754, which is R70 in August and R70. I want this rectified and sorted out by no later than the 19 September