If it's a small crack why not try it yourself?
If not just get a blue tack and duck tape over it for now (I never tried but I'd do that if you don't know solarez...) and have it fixed properly later when you're less in rush?
Can one of your mates do it for you?
Let's be little bit more careful before naming and blaming someone for letting you down for something "small" and at "short-notice"... I take no side but bit unfair to name drop it like that.