problem with my nokia lumia 920?

Okay so I bought Nokia Lumia 920 like 9 months ago and started using it with my old sim.Now I just got myself a new phone no.(i.e. new sim) but its actually not working.Earlier I thought it was sim card's problem as the phone was working just fine with the old sim(on re-inserting it in the phone)..so I got new sim card and guess what,it still is not working..Even more strange is the fact that,with both the new sim cards the problem is only with outgoing calls i.e. I am not able to make any outgoing calls and rest all functions are working totally fine...and even stranger is that when I use my old sim card,there is no such problem...please help...