Actually, expiration dates on gift certificates and cards is illegal in at least California, Hawaii, New Hampshire, Massachusetts and Rhode Island. And some states (PA for example) do not let the merchant keep the 'unearned' funds... they are transferred to the states 'unclaimed funds' account.
As for Illinois...
"Currently, retailers who offer gift certificates or gift cards are required by law to report the value of a gift certificate or gift card as unclaimed property after it has not been redeemed for five years. "
(765 ILCS 1025/10.6)
Gift certificates and gift cards.
(a) This Act applies to a gift certificate or gift card only if:
(i) the gift certificate or gift card contains an expiration date or expiration period; and
(ii) none of the exceptions in this Section apply.
(b) This Act does not apply to a gift certificate or gift card that contains an expiration date or expiration period if:
(i) the gift certificate or gift card was issued before the effective date of this amendatory Act of the 92nd General Assembly;
and
(ii) it is the policy and practice of the issuer of the gift certificate or gift card to honor the gift certificate or gift card
after its expiration date or the end of its expiration period and the issuer posts written notice of the policy and practice at locations at which the issuer sells gift certificates or gift cards.
The written notice shall be an original or a copy of a notice that the State Treasurer shall produce and provide to issuers free of charge.
(c) Nothing in this Section applies to a gift certificate or gift card if the value of the gift certificate or gift card was reported and remitted under this Act before the effective date of this amendatory Act of the 92nd General Assembly."
Source:
http://www.legis.state.il.us/ilcs/ch765/ch765act1025.htm
So, with the above information, I suggest you returning to the business and asking them if they will honor the card or if they will have to send the funds to the state. I would ask, "Wouldn't it be a much wiser 'consumer' decision to allow me to use the card and be happy, then to refuse the card and piss me off??"