File GSTR-3B as usual. In month of October you can claim input credit for tax paid.
This credit will remain in your input credit ledger and can be utilised in future against any tax liability arising.
chatCommentsAre you sure about it as because I am hearing something different that this the ITC on RCM can only be adjusted in filing of October, 2017 GSTR-3B and can't be carried forward after notification for revocation of RCM under section 9(4) of CGST Act & section 5(4) of IGST Act came into effect, but at one point it is also confusing if that act had came into effect, why the GST portal never blocked the option in GSTR-2 - Abhishek RoyYes claim it in October return. You can do it even letter in GSTR-2 also. If you have paid tax under RCM nothing should prevent you taking input credit. No form can over rule, Act and law. - GST Payer