Stock invoice

Dear Sir,

kindly advise to me We are supplier of Marble cut piece and we have 2 firm. In first firm We have full stock.We sale the cut pieces to debtor's and debtor' has release the payment.but due to some mistake We have issued the invoice from 2nd firm in which we don't have any stock.I n books of account stock are showing nagtive(tally) We also filed GSTR-1 please suggest how to match stock in books.