I don't know if the email provided for the purpose of sending the 'resume' link is retained, but certainly if the survey has an email field (?) that information would be retained and saved in the database. The save and resume submission that is incomplete is of course viewable in the Machform admin area (you just need to filter on "incomplete" submissions).
For the survey itself, you could set Machform to not save the submisison in the database, but that's not a form-by-form setting, it's either all saved to the DB or none.
Not sure if I have answered the question or missed the point of it. If you have technical questions about this, the forum is not the right place to ask since it's not an official support channel. Please submit a ticket to Appnitro (through your customer area) if you have concerns about whether the email used for Save and Resume is actually retained,or just momentarily used for that one purpose of sending the link