I was a manager at Whole Foods for years and have dealt with thousands of returns and customer complaints about food. I am sure the bakery will take the cake back and give you a new one, but I don't know if it is really fair for you to complain- especially if others have eaten the cake at this point. If it was only for you and you just took one little piece, that's one thing, but if your family has finished more than half of it, I would be embarrassed to bring it back! (I once had a customer try and return about $150 worth of lobster SHELLS- claiming that the meat had 'all gone bad' and they had thrown in out, but were bringing the shells in to complain for a refund, lol.)
Unless you and your husband specifically requested that the bakery not use almond extract in their cake, then no, sorry. How on earth would the bakery know not to use it if you did not request it?
Many white or yellow cakes are made with different flavorings- almond or vanilla, etc. If it is not listed on the ingredients list, are you POSITIVE it even has almond extract in it? Sometimes if the amount of seasoning or flavoring is VERY SMALL in comparison to the other ingredients in an item they do NOT have to list it, because the amount used is so small. Usually with a nut product they will list it just to be safe, though.
The bakery did nothing wrong-UNLESS you pre-ordered a cake specifically without almond extract.
But if you did not order a special cake made up ahead of time to your specifications- but just sent your husband to get a random cake, then how could they know?? Next time, order it and be specific about what you want.