I can get why they change their terms but this is something that they should have expected also so they didn't make the best impression here. Well, Messi scored again against Croatia so an odd of 3.5 was really a good valuebet!
It could be because this giveaway has a set amount of funds that will be spent by Duelbits throughout the 25 days, so when one day has spent enough then the rules are changed, because this is only day 14 there are still 11 more days where players can take part in the challenge and get prizes.
Unfortunately I'm not betting on Messi scoring, maybe in the final if there is a odds boost might consider it.