I see more and more people getting fucked by sponsors.
Here is what to do.
1: The current bigger sponsors you use. Ask for a contract that say basicly the same as their terms + their payouts. And that the contract will only be invalid once a new one has been issued
2: Stop by
www.intrum.com (Intrum Justitia) a international debt collection agency. Fill out the info on their site about you wish to be contacted. someone from Intrum will contact you and setup a meeting so you can get all info about what, why and how
3: Sign a contract with them wich cost around $300 per year (and you get a really cool stamp to put on your final invoice also)
4: Once a sponsor is not paying make a invoice put the stamp on wait 3 days to get a response from them
5: No response? pay $50 to Intrum to start the case against and send them all info you have about the sponsor
6: Sit back and relax untill they collected your money and think about all the money your sponsor is using for lawyer fee's
7: Get your money at Intrum where 6% to 20% of the total is deducted depending on the case
8: If the sponsor can't pay because of their financiel situation no problem they will put the sponsor on a watch list and keep track of their financial situation if it improves they'll push the case again
That's the basic idea.
At least it is worth a try for anyone that is owed more than $700-800 from sponsors

Hope this could help a few people out their that really NEED that missing check