Can you share with us what mistake led you to being dropped by your biggest source of revenue? In these sorts of things often an 'after action' report works out pretty well, it goes "Oh we blew it, we did X, this caused Y, we've changed P, Q, and R so that X can't happen again." Startups do that all the time, one of the more common ones is "we didn't secure our servers and gave out everyones login information" or something along those lines.
Restaurants are particularly hard places to succeed because not only are they regulation rich (so there is a lot of energy expended in dealing with the health department) they are abused by fickle tastes. (Ask anyone who has tried to run a Greek restaurant in the south bay for a while now, not sure why but they are darn hard to find)
Your web site talks about attending food festivals, do you have a truck? The Curryupnow folks gave a pretty textbook example of how to build a following by driving to specific spots, tweeting about it, and introducing their cuisine to folks outside their building. That skipped the whole 'get us a catering gig' problem which is, as you've experienced, a challenge.