webmail deletions morph when email client connects

[#1]

Today I logged into my plusnet mailbox using webmail and deleted the spam leaving 4 real emails.
This evening, when I got home, I fired up my PC email client to pick up the emails.
To my surprise, the real emails I had left in the webmail inbox had become 4 of the spam emails I had deleted.
The 4 real emails were nowhere to be seen.
Q1. How can this happen?
Q2. Any chance Plusnet can restore my emails from today?

[#2]

You've probably been caught by the old and infrequent bug where webmail is dispalyed a different list to the server (seemingly caused by a cache failure),  if you don't pay attention to the preview its easy to inadvertantly delete the wrong email.  A couple of old threads related to the problem  webmail displaying wrong message and errror loading mesages
If your webmail settings don't clear the deleted mail on exit, they might still be in there,  or the only other hope is  that they were present before a backup was done and someone from Plusnet can restore them.

[#3]

Look in the Deleted Items in webmail - if they are still there you should be able to move them back to the Inbox (right click and Move to...)

[#4]

Quote from: kmilburn

If your webmail settings don't clear the deleted mail on exit, they might still be in there,

As a result of another webmail 'bug', I had to turn on 'clear deleted mail on exit' some time ago.