How to unpublish content when form submitted and notify a user by eMail?
The Rules module is, for sure, your best bet for addrerssing this (therefor +1 for this question already ...).

Can you further enhance (edit) your question to explain what you have tried already using Rules? And what worked, or failed, and what the remaining questions are while using the Rules module? I.e.:


which events?
which conditions?
which actions?


For anybody not familiar (enough/yet) with Rules, checkout the 32 (!!!) great, and free, video tutorials Learn the Rules framework, organized in 7 chapters. Possibly also the similar set of 8 video tutorials about the Flag module, often considered as a natural complement to the Rules module.