ITC Not Reversed for Non payment within 180 Days

In one of our case payment to supplier is not made within 180 days and ITC reversal as per rule 37 of GST is also not made. It is for FY 2018-19. But after 300 days payment is made to supplier. Time gap between Date of Invoice and Date of Payment to supplier is 300 days. Now Notice is received for reversal of Entire ITC.

Is he liable to pay only interest for the delay in payment to supplier or is he required to reverse entire ITC ?

Anyway as per GST Act ITC is available when registered person subsequently makes the payment of amount towards the value of supply and tax payable thereon to the supplier thereof.