Empty gift card recieved?

[AaHu]

Hi all,
at the end of my contract in July, my line manager alongside another colleague, gave me some chocolates and a card with 2 'YOU CHOOSE' gift cards inside (with a £25 amount on the top of both). I've decided to buy myself a bag so I have gone online to redeem and only one card is active.
the other one reads error.
I am
on good terms with my line manager but not sure what I should do? I Feel like that's £25 down the drain if it was paid for but if it was an error I don't want raise it?

AIBU to raise it?
Or AINBU by raising it?

Is there a way to contact the gift card provider and ask them to look into the error, in case it's an easy fix? That would be my Plan A. Once you have all the facts you're then in a better place to decide whether to reach out and let her know that the card doesn't work.

If the card has a problem that can't be remedied by the provider, I'd approach her with the tact of "just letting you know that I contacted [company] after experiencing problems with the card. Just in case you wanted to contact them for a refund, its better in your pocket than theirs!" That way, you're passing on the info in a friendly, non-cheeky/grabby. Hopefully she would rectify it and pass it back on to you but either way, the company shouldn't profit.

Could they have bought them in a supermarket?

They have to be activated by the supermarket, so something could have gone wrong at that stage.

I had this once with a gift card for my daughter (Next). It was from a friend, but not a close friend iyswim. There was supposed to be £15 on the card, it was empty when we got to the till. Really awkward. I ended up paying instead, and didn’t raise it with my friend because I know how hard it is to prove whether gift cards have been activated or not and disn’t want to put her through the stress of potentially having to fork out another £15 if it couldn’t be rectified.

I learned this recently from an experience in Morrisons where I bought a gift card, paid for it at self check out and the till roll ran out so I didn’t get a receipt. The assistant could not reprint the gift receipt and said that gift cards are completely non returnable, even if there was a problem with it it - they will not refund! Put me off buying them in the future tbh.