Query on ITC on Invoices issued with Provisional GSTIN –

We have provided services to the recipient of our services in the period 01/04/2017 to 31/03/2018 and issued invoices to them with provisional GSTIN. Later due to non-completion of the PART-B of the GSTR-26, the provisional GSTIN gets cancelled.

After that, we applied for the New GSTIN and got the registration with date 09/04/2018. Upon that, we paid all the tax liability amounting Rs. 16 lacs (approx.) for the invoices issued to the service recipient of the period 01/07/2017 to 31/03/2018 in the New GSTIN and Entered all the invoices issued in the GSTR-1 with a date of invoices as 09/04/2018.
(as a provisional number cannot be re-activated upon cancellation).
 
Our Service Recipient has taken the ITC for the Invoices issued to them with Provisional GSTIN (later revised by mentioning New GSTIN). Since the Date of Invoices is prior to the date of New GSTIN (i.e 09/04/2018).

Our Service Recipient is in uncertainty that whether the ITC claimed by them will be allowed to them or not, as the actual date of Invoices and date of invoices reflecting in GSTR2A are different.

So, please guide whether our service recipient will get the ITC claim of the Invoices issued to them with Provisional GSTIN which was cancelled later and tax liability of whom paid in new GSTIN return.?