Vodacom
I buy from vodacom, they send me to digital planet

I bought a Nexus 7 online from Vodacom. I am having massive problems with it - standby times have been reduced to less than a day from more than a week. I take it to vodacom. More than a week later I call them to ask on progress and they tell me they did not send it anywhere. I must come fetch it and now call digital planet? How is this my responsibility after having bought it from them???