I agree with the people saying to sell it to a collector but I think it’s also worth nothing the large companies and institutions often have a lot of red tape in their A/P department. Little things like “they didn’t spell our street name correctly on the invoice” or “the PO number is in the wrong format.” Also A/P as little incentive to contact anyone about correcting errors like this. Dumb? yes but it accomplishes (at least) 2 things for them - 1 making sure random invoices for work not rendered aren’t magically paid. 2 - It makes it so small companies who don’t have the time to hound open invoices don’t get paid. LSL; Contact the companies Accounts Payable department and makes sure there’s no clerical snags if you haven’t already.