unredeemed
adjective
uk/ˌʌnrɪˈdiːmd/ us FINANCE
used to describe something that has been given as security on a loan, and which the lender keeps because the borrower has not paid back the loan:
Unredeemed articles become the property of the pawnbroker at the end of the period and may be sold in order to repay the loan.
not exchanged for money or goods:
Retailers gain a huge amount of revenue through unredeemed gift cards.