* Regarding the sealed food, I have reported faulty packaged-food items to the manufacturer two or three times, and in each instance was provided with a coupon for a free replacement.
* Regarding the store not having an item that they thought they did, you may find that there was no agreement in place requiring them to make it right, especially if no payment was exchanged, or if said payment was refunded. You may be limited to the “court of public opinion” that is Google Maps reviews etc..
But for the other two items, small-claims court, optionally preceded by a strongly-worded letter from a lawyer: You may find that an hour of lawyer time is worth it, to write such a letter and to generally act as a ‘sounding board’ for your issue.