Bad Service / Huge Bill

On the 30th of April, i went to Mtn in Tygervallei. I app**** for a router. The router will cost me R149 a month for 2G and for 24 months. I asked her several times will this thing cost me R149 per month for a 2G, and her answer were YES! Also asked her when i get home will this router work, and she said YES! Got home, and it didn't work, long story short, i had to phone twice and a other Woman help me (thanks Suzette). The router worked, i was happy till I got an sms saying i have reach my credit limit??? How is that possible? because my mtn contract is a topup and the router must stop automatically at 2G! BUT NO..it was an open router??? She didn't tell me anything about open contract. And now I have a bill of R1511.15 (R200 for my phone - Topup thats correct) and the other money is the router! I tried to phone again, but now Mtn in Tygervallei is only a Walk In, and i cant phone anymore. I live 250km from Cape Town. So What now??? Im really not impress with this service. Its alot of money, and why would I have a Cellphone Contract of R200 a month (topup) and a open Data/Internet contract? It just don't make sence.