GST notice u/s.46 in form 3A

Hellow everybody,
A very small trader (having turnover less than 20 Lakh but registered voluntarily as getting business without registration was difficult in his field) registered under GST has received notices as said in subject for failure to file GST returns from November 2021. His customers have not paid him for sales since November because of which he is facing financial issues and was not in a position to pay due GST. Above notices have been received for November to January. He is also not in a position to raise any loan for payment of GST.

What can be done in such case? His registration might get cancelled besides some stringent action from department. Please suggest.