Sorry you didn’t ask before ruining 4 bags.
You do NOT need a perfect vacuum with the UMAi Bag to achieve proper aging! You don’t even need a Food Saver!! What you can do instead is to place the meat inside the bag, press the bag against the meat, and then gather the open end of the bag together and insert a flexible straw or piece of tubing into the gathered end, continue to squeeze out any captured air and then just suck any remaining air as best you can – then quickly yank out the tubing and seal the bag using a bread twisty – one of those paper or plastic “bread twistys”.
In your specific case I would still try to salvage the bag by puncturing a small hole in an end and then follow my method described above and when satisfied seal the hole with a piece of strong mailing tape.