T mobile broad band dongle says no coverage

I recently bought a t mobile huwai mobile broadband dongle. The dongle installed on the computer okay. I have inserted the sim correctly but when the t mobile screen comes up it says there is no coverage even though my sister has the exactly same dongle and hers Is getting coverage with good reception . Does anyone have any ideas as to what to do?

Try taking the laptop and dongle to another location and see if it works. Otherwise take it back to the shop, it could be a faulty dongle.

and what happens if you use your sisters dongle in your laptop?