Bad service

I received the router 2 days after I paid, I really applaud them for the quick service. I called immediately to get my sim card activated as according to the call center it was not activated. I have been calling since Thursday everyday but still noone is assisting. I was promised that someone from technical department will call me, still no call, I am worried that if am getting such a horrible service from the beginning what will happen if I encounter some problems in future. I am being send from pillar to post.