Airtel — 4g lte dongle - network issue

I am using this postpaid 4g lte dongle from last 2 years but from almost 3 - 4 months, i am facing the network issue. The dongle will connect for 10 - 15 mins and then it will be disconnected and i have to reconnect multiple time. I have complaint multiple time but every time they have guided me to reset my dongle, id, and password which worked only for 1 days then again the same issue.
The current ticket no. Is 78073665 which created on 25th jul but till now there is no progress. They have called me once to check whether my issue is resolved or not without doing anything. I want to change the old plan and want to take new plan but if i don't have the network then what i will do with the new plan. I am paying much higher rate as compared to current plans in the market.