Faulty Router/********** After Sales Service

Initially when I went online and requested a call letting them know I'm interested I got a call back within minutes. I have received my router everything was going well until I plugged it in and it's it worked for a bit and then suddenly switched off. It's now been 2 days and 5 requests later and I have not received a call back from them. Even the two SIM cards that I received from them do not work.