First off, this is just a suggestion, with no specific expertise or experience! Anything you do is at your own risk.
It sounds as if the lock mechanism is only partly engaged, but can you hear the mechanism operating, when you operate the badge switch? If you can, I would suggest going inside the boot and pushing up on the inside of the hatch, while someone else operates the switch. Get your helper to pull the switch then push up on the hatch while they gently pull the badge switch, as you would when opening the boot normally. Hopefully, a bit more force will unjam the strap.