Dstv multichoice worst service recieved yet!

The WORST service we have ever recieved from dstv multichoice. We bought an explora ultra on price lock end of november 2021 we paid everything in full the amount was over R2000 we paid for installation we had everything set up we just waited for the decoder. Well we waited until end of march 2022 when we decided to go buy our own decoder at Game because we never recieved one from dstv. We ended up installing it ourselves. So we phoned dstv to activate and everything was done by my husband and me. We asked just to make sure what our monthly installment would be they said R565. A few days ago we recieved an sms saying our next installment will be R1002.12 so we again went to dstv to sort it out and they said they were on it and still we are waiting no one talks to us no one helps us. We also requested a refund for the decoder we bought november last year and still no answer... we do not know what else to do.