ECommerce Wrong return Gst related treatment

sir I have sold goods on meesho. now I have received over 100 goods in which the product which I have sent is not received instead of that I received something else which does not have any value. Now as per meeshos calculation I have made sales return entry but now I have lost that product then what should I do. as that product is now only in stock in books of accounts in reality it does not exist as it is stolen. should I show that at theft and pay gst of that product to goverment or there is any other method of treatment.pleaae let me know