This gst ???

Revising inovice is the only legal option as RCM is not applicable no every situation there is a list of specific situation on which RCM is applicable and how can you consider them as simple expenses and escape from GST.You can not do any of the above option you stated above.

HSN code and GST Number of Supplier and Buyer is Must on Invoice........ if there is no GST number of Buyer on Invoice then Send the GST Number to Supplier,,,,,, 

Don't get panic.

1) Call your supplier.

2) Inform him your GSTIN No.

3) Request him to please fill up your GSTIN Details in GSTR 1 when they file....

4) Send your GST Provisional Certificate through mail, Whatsapp, Telegram, Hard copy what you want...........

Once your supplier mention your GSTIN in his GSTR 1 then you can take the ITC.......

If it will be not reflect in your GSTR 2A then you can add this in your GSTR 2.........

So simple...........

That's All.......................