I am pretty good about using my deal-a-day certificates before they expire. But one recently got past me. It was a Living Social deal - I paid $25 for $50 worth of merchandise from a store near my parents' house. I figured I'd have no trouble using the certificate before the expiration date printed on the voucher. It turns out I overestimated how many times to grandmother's house we'd go.

I figured I was still safe, after reading several articles in recent months (including one by Star Tribune shopping columnist John Ewoldt) about how these deal-a-day sites require merchants to accept the vouchers for the price paid even after they expire. In my case, I assumed I would receive the $25 I paid, not the $50 worth of stuff I could have purchased if I'd been on time.

Not to do so would violate federal gift card law, which requires gift cards to be valid for five years. That's far longer than the typical expiration date printed on a deal-a-day voucher. Several lawsuits have been filed, including in Minnesota, claiming that the printed expiration date violates this law. I'm keeping my eye on these lawsuits. Stay tuned.

Back to the story about my expired certificate. I was turned down, told that the coupon was expired and it was up to Living Social to refund my money.

I left the goods, walked out, and got Living Social spokeswoman Maire Griffin on the phone.

If they don't, call, e-mail, or send Living Social a tweet and they'll fix it, Griffin said, either by speaking with the merchant or refunding your money.

I called the merchant back and was told they would honor my voucher the next time I come in. I don't want to single out the merchant, who I could tell feels badly about the situation. She said Living Social described the deals to her as coupons, and that they should expire like coupons. She's written letters to the Department of Justice and Attorney General saying so.

Having to keep track of who did and didn't use their paper certificates over a five year period is cumbersome for small businesses with limited resources, she argues, and worries that the low-tech system is ripe for fraud.

All in all, she said the Living Social deal was a major money loser for her.

How about you? Have you tried to redeem an expired deal-a-day voucher? What was your experience like? Should merchants be required to take them?