Trai — 2G network instead of 4G at every night 1.08 a.m.

Dear sir,
I have airtel postpaid 4G sim since last 2 month.
I have data plan with 4G network but i dont get the 4 G internet even charging for 4g.
On every night 1.00 a.m. to 7 a.m. receiveing 2g net inplace of 4g data plan. I have also filed complaint in airtel thanks app on 18th July 2021 but its stil unresolved. Even dont received any call from service department.
If you are not able to provide 4g network to your customers than why are you selling 4g. I advised you to Provide 2g network to your customers because you dont know what is the meaning of 4g network and its services.
I have also mailed about this to nodal office of airtel but till date no resolution.