Deleted emails from trash

Hello,
All my emails were mistakenly deleted and then all my trash emails were deleted. My email folders are gone too. Someone was "helping" me change from an iPhone 4 to a 6 and because the old phone was already disconnected and I was using the new one, he figured it would be a good thing to delete my personal info from the old phone, assuming everything would stay on my other devices. I tried your suggestion with the drop down menu several times, but nothing happened. Is it all gone forever or is there anything I can do?
Thanks in advance for your reply.