From looking at the site, there are seo best practices not being followed, but I don't think that is the reason for the drop (You have multiple H1 tags on the home page, there should be only one)
The Schema code shouldn't impact the site in any negative way as well.
Even if someone was link spamming your site, Google wouldn't count that against you, otherwise seo would only be about link bombing your competition!
If Google came to crawl the site and nothing was there, it might also have been the deep crawl, and that might account for the missing snippets.
The key here is not over-react. It sounds like you have everything in order, and might have just been a victim of bad timing.
I know it's hard to be patient, but give it a week to see if the snippets return once the fresh bot has hit your site. You might also want to send a message to Google through your Webmaster account, they are pretty responsive.
Good luck!