Parents were in US July 2008, filed for an I-94 extension end Aug 2008 from Dallas, which was submit to VSC and subsequently routed to CSC their port of entry California. Extension was denied end Jan 2009 (guessing since they had extended 2 months the previous visit in year 2007). They left Mar 2nd 2009 (meeting the 30/31 day exit requirement). Are they ineligible for GC? If so how long? Is there an alternative?
It does not look like they were unlawfully present for over 180 days. So, I don't see why there should be a problem with the green card.