Airtel — not getting calls

Hi, i got the 4g sim for my airtel connection. Ever since i got the 4g sim although i have all the signal but my no is always not reachable. I called in the airtel customer care and got a lame advise to just restart my phone which i already had tried multiple times. I was also advised that this will be resolved within 4 hours. The problem persists. Now i am looking to change my protal to other service provider. Take my feedback and don't even go for 4g sim at all it sucks big time.