If you provide a freelance service, it is inevitable at some point someone is going to cancel a booking right at the death or even worse right in the middle of a booking. Your natural reaction may be despair and disbelief followed by frustration and a need to take them outside for a flogging (did I say that out loud!?) but remember the agency (your client) is also treading a fine line with their client who may also have just done the same thing. A little understanding and a clear, agreed set of T&Cs with a reasonable cancelation charge before you start work can go a long way to building a solid working relationship.