Problem deleting my emails on webmail

[#1]

I am using a Mac Powerbook to get my emails on Plusnet webmail. I was recently moved to Plusnet from Madasafish. I have been having a problems deleting emails for the pass few days. At first I was able to press 'control' and click on the delete icon. Today I have had problems deleting even one email at a time. Different boxes pops up and cover the delete and also spam icons. Other messages appears, such as 'error' The email symbol continually spins and this 'grays out ' the delete icon and spam icons. Nearly all emails in the mailbox are spam and I would like this to stop.

[#2]

Can you do a screenshot so we can see what boxes you're referring too? Don't post any sensitive information though! You might need to blank out any visible emails using a paint program.