TIME LIMIT TO CLAIM ITC IF TAX PAID UNDER RCM AFTER LITIGATION For Fy 17-18 & Fy 18-19

In my opinion ITC on such rcm will not be available.

RCM liability started as per section 12(3) coming in force w e f Feb 2019.which may
as deemed till 31 January 2019.

@ Imthias did not understand what you mean to say

Reverse Charge Mechanism (in case of supplies made by unregistered persons to registered persons) will apply, starting from 1st Feb 2019, only on specified goods/services and specified persons. The list of persons or items subject to the provisions is yet to be notified. 

2018 RCM notification b note

I think this is not allowed to take credit as it will be time barred.

I have by now got the point that it may not be allowed, but i still fail to understand what is the concrete evidence that it's not allowed to be claimed ?

Technically , the Credit available for RCM is when it is paid .

And in regard to Section 31(3)(f) , the person who pay tax under RCM is required to Issue Self Tax Invoice on DATE OF RECEIPT OF GOODS OR SERVICES.
Thus the documentary proof to avail ITC in case of RCM is Self Tax Invoice as prescribed in Rule 36 .

So the Self tax invoice issued in mentioned periods the credit is not available.

During this period RCM is in silent ,so further supply of same will lead to difficult situation. Supplier already collected opt against proportionate Itc of same goods.
Hence I st supplier of same goods may be block the Itc in his return,Itc allowed further supply made by buyer.Opt fully deposited to govt by 1st supplier.unless which goods exported by another buyer and who can not claim refund.
Please verify Previous Vat section 6 (2).

I think in the month of payment it is available, as ITC for RCM is available in the month of payment