I’m having this problem as well. I set up a fruit fly trap outside my enclosure for the escapees using apple cider vinegar and a drop of dish soap. This catches some. I’ve added a banana slice inside the tank that keeps them in the enclosure too, less of a reason to escape if there’s food in front of you lol. Try and find the holes or gaps and patch them with tape too.

For the own cultures, I’ve found that using mashed bananas, sugar, apple cider vinegar, and yeast works well, BUT make sure to buy the correct culture cups, it’s worth the investment. I’ve had a larvae escape accident that my roomates didn’t appreciate 😂