Debit order more than agreed

On air sold us a Explora decoder and we have been paying our R149 religiously for more than a year. then they phoned and sold us a Wi-Fi connector the agreed debit order was R29 they have been taking R129 from the first month. I have emailed them but have not received a response, then suddenly January they started taking an additional R17 for FONESURE. I would never had taken the Wi-Fi connector if I knew it will cost me R129 a month ( for a device that's not even worth R700) They need to contact me asap because if all of these strange amounts going off my bank account again end of this month I will be sending back the Wi-Fi connector ( I have not even open it yet) because I can't seem to sort out this issue.