Itc reversal on returned rejected goods

Sunil (Trader)     02 April 2018

Goods were received in February for which GSTR 3B is filed showing claim of ITC under Item 4 (A) (5). The said ITC has not been used from the electronic credit ledger as there is no sale in February

As goods are rejected, vendor has issued a credit note and taken back the goods in Month of March. How to reverse the ITC from the Electronic Credit Ledger in March month. As there is no sale in March and purchase of supplies in March is less than the amount of reversal. Unable to populate any negative number in the Item 4 (A) (5) of GSTR 3B. How to reverse the ITC on return rejected goods when the return takes place in the next month?