tenant did not give notice or pay rent

[Jimmy S.]

Hello again

Long story short, lease expires on 2/1/15 and renews for 1 year without 30 days notice. I have last month and security deposit. They did not pay this months rent. They also did not say they are moving out or did not give any notice. I am trying to contact them the last couple days but no luck to see whats going on.

What should I do?

 Assuming they are moving out which I really don't think so or send a pay or quit notice and can I b/c this could be their last month and its already paid for but did not give any notice.

Thanks
Nate