Bad bad service

DStv has takes more money that was agreed upon when I called the girl I spoke to told me that there was a problem with the debit order system they will refund me,I called back the second time and the guy I spoke to said no he will load the refund for me and it was never done when I call back the 3rd time the lady I spoke to me tells me no the amount was correct it’s because I changed my debit order date that’s why I paid so much. 1st of all why wasn’t I informed from the person I spoke to that the debit order will be much more then normally 2nd of all why did they take so much money for simply moving a debit order date and lastly why didn’t the 2 consultants I spoke to first why didn’t they pick it up why when they checked my account they could see the money that was taken was way more then I normally pay. I want my refund that is a lot of money that was taken and I wasn’t informed of extra costs being taken from my account anyway shape or form so I want my refund