This is what I garnish from the rules:
The Contest is only open to natural persons who (at the time of entry): (i) are residents of and are physically located in Canada; and (ii) have reached the legal age of majority in their province/territory of residence and have valid government issued photo identification for verification purposes (HOWEVER, as noted below in section 6, in order to participate in the Tour “defined below”, the confirmed winner must be twenty-one (21) years of age or older and must have a valid drivers license – see section 6 below for details).
If they refuse to give you the money, as you're not under the age of 21, I'd argue, I still have the rights for the trip, but won't participate in the Tour, as that is what it clearly says in the rules. I don't know exactly what section 6 is but hope it works out for you.
Plus, if this was mandatory, the rules never specified that, and on top of that, they were willing to give an alternative either way, so they can't be that social media crazy and have one of their winner's in the tour's running. Good luck! And good luck everyone, christmas contests soon, and I usually have better than average luck at those.