let me add one comment......
When an official / assignor provides contact information (such as home phone, work phone, cell phone, email address, etc.) for any communication needs, he expects to be notified of any changes accordingly. Furthermore, if multiple forms of contact are made available, efforts should be made to
"run down the list" until confirmation is obtained. This goes both ways! Do not simply leave one message.
Now, although argueably prudent, I do not make it a habit to contact my assignor (or an AD) for a scheduled game just to be sure it is going on as "booked". That is one reason why we have contracts. This is also a good reason to make use of contracts; it allows you to get paid when procedure is not followed!
If you do not use contracts, you might want to consider implementing them for your own protection here is a sample:
http://www.mhsaa.com/services/offcon.pdf (.PDF)
http://www.mhsaa.com/services/offcon.rtf (WORD)