Samsung and IMAP

[#1]

Hi
My wife's Samsung has IMAP set up, but when she deletes emails on her phone they are deleted and then return on the next refresh.  Clearly they're not being deleted off the server, just her phone.  Does anyone know what I can do to force the deletion off the server?
John

[#2]

Is there a setting option (on the phone) so that when messages are "deleted" they are actually *moved* to the Deleted folder rather than flagged for deletion? I think the mailbox has to be "purged" to physically remove flagged messages.
Emptying the Deleted items folder might be a file menu option.
David

[#3]

I couldn't find a setting. I was hoping someone could point me to where it is