Airtel — 4g mobile data not working

Address:

New Delhi, Delhi

I recharged my mobile data for 399. 1gb/day for 70 days. First it worked good but now the problem is that it sometimes work and then stops immediately. And when it works it gives a 2g speed
. Plz resolve this problem it would be a great pleasure. I hear that airtel 4g is the fastest network and that is why i used it. Please resolve this as soon as possible