Advance Received on 31.03.2021, Services not Rendered for Covid, GST Applicability

Dear Experts,

Greetings!!!

I have One query, We have received Advances against Services Dated 31.03.2021, but due to lockdown and covid not able to render the Services. Which is still uncertain when we will render a service today 18.05.2021.

Here the problem is due to change in the Financial year and the amount received on the last date of F.Y. i.e.31.03.2021

1) Did we have to pay a GST on Advances Received?

2) if yes, GST liability will be computed from 31.03.2021 Or 30.04.2021 (assuming 30 Days). 

Kindly reply

Thanks in advance to expert team.