Hi there all. I found that this worked for me.
I tried switching if the phone and other methods. This is what worked for me.
1) delete the email acount from your phone in settings. If its you icloud email taking up space then youll have to manualy delete the emails from your phone
2) use an app on the istore that clears cache memory. I used Memory & Disk Scanner Pro - Check System Information by Phan Minh Nhut
https://appsto.re/za/Lzt72.i It has a traill period that alows you to use it a few times. I used it once and then deleted it afterward. My emails took up 1.05 gb and after i used the app it cleared it.
3) i suggest using an app like gmail or yahoo to use for emails. It takes a lot less space.