This doesn't quite answer your question, however may help you.
I've had problems with my fob in the past and I had to take the cover off where the battery is - sometimes the battery wasn't making a good connection. Is this light coming on when you press it, this may be the problem. I'd another which had the wrong size cover on it, so the buttons never quite lined up. - Bear in mind, this is two problems in close on 10 years.
They are or can be flimsy, but incredibly expensive for what they are - typically 100 - 150 Euro.
Another alternative to help you over the next couple of days, if you know someone else with a fob - they're pretty much generic. Where you put the battery, you can change the number which is the code - but you need to know someone who doesn't need theirs until you're sorted.
Can't help you on the legalities of your situation, I don't know enough,
Jen