How do I get the builder to take action?

I bought into a brand new condo a year ago. The builder is running low on cash and is starting to stop taking care of the yard work, cleaning, etc. He has yet to fix the punch lists on the 14 completed units (out of 37). His work number is no longer in service and the only way to get in touch with him is through his cell phone, which he doesn't answer most of the time. To make matters worse, I believe he just got foreclosed on.