How to record transactions of a purchase and its refund in the following month?

How to record transactions of a purchase and its refund in the following month?

I made a purchase of a product from Amazon in the month of May, Total cost - 1099 and had to pay IGST - 167.64. I filed the GSTR-3B and it was easy as a cake.

Now in the following month of June I received a complete refund of the product. How do I record this, I tried recording it as vendor credits, but in the GSTR-3B form it's showing as a negative ITC, which I cant push to GSTN.

Can you take me through the process of recording a refund event in Zoho Book.