Dstv Bill's me for no services over 1 year 7months

I been paying for dstv for 1 and half years and kept calling in as couldn't watch due to no reception Was told swop recorder which I did twice still nothing I complain to dstv they said sorry since u changed decoders we cant help you with voucher I have as they said it's now dish which problem. If only I was told about terms and conditions then I wouldn't have switched decoders and lose voucher. It cost me money over 650 to fix dish lnb. I want dstv to refund me all my money I been paying for not using dstv due mistake the call centre made. I spent time and money I never get back on visiting centre calling dstv and external dstv services