DPP order error

On 9/14/2015 I order a dstv explora. I chose the 99 rand a month package the next day they deduct the 99 from my bank account. A few days after that my explora came with the courier. And then I payed a acreddet agent to install the explora with the smart lnb and a lager dish. The agent charged me 1600 for the installation. The next month they deduct 279 from my bank account but not the 99 rand and November also they deduct the 279 but not the 99 on the 6 November they credited my dstv a count with 279 and they change my dstv explora package from the 99 package to the full dstv package of 800 'n month so now I have to pay 800 n month for my explora but I didn't buy it for 800 I bought it for 99 and on the 800 package installation is included but I payed for the installation 1600 so how is it possible for you guys just to change it as you please.