I think we have all had these situations. If possible in calls typically have the best chance of happening when comparing to out calls and I’m sure a book could be written on all the various excuses. Personally I think 15 minutes if no contact at all and 30 if he at least contacts you. The excuse I have heard the most if you do end up in contact: oh f—k, I fell asleep, sorry” LOL Well, he might as well go back to sleep as he has been cancelled!