problem reducing mailbox

[#1]

I've had an email from Plusnet to say my mail box storage is getting full. The instructions how to do this don't make sense, webmail is very slow to load and says my various mailboxes are empty which can't be right. Having a ridiculously slow broadband speed (2Mbps if I'm lucky). I can't seem to find out how to raise a ticket to get this sorted (the website just sends me round in circles) hence this plea for help. Thank you!

[#2]

@outinthesticks 

I have just been through this procedure for a relative. To avoid failure messages I found it easiest to open a page of emails then select the page of emails by selecting the first on the page then the last by holding the shift key down. Then  drag these into the deleted items box. Once in the deleted box right click the deleted items box and select empty. 

[#3]

thanks but I don't want to delete a whole batch of emails indiscriminately. I want to arrange them in order of size and then delete the largest. Disappointed no response from Plusnet. 

[#4]

Hope you got this sorted?  Yes, Plusnet coverage here is not adequate, which is a matter the SUs have under discussion with Plusnet.  Something I will raise again today.

Frankly sorting email content is generally better done on a PC based email client.  Sorting emails by size and knocking them off is a most sensible strategy ... however there are know problems in the third party round cube email client when working with a specified sort sequence.

Other things which can mitigate delete performance issues is to do an "affirmed" delete (rather than a move to trash for deletion later) by holding down the SHIFT key when pressing the DEL key.  This works in both webmail and most PC based email clients.

WARNING SHIFT+DEL is not recoverable so be certain absolutely that you do not need the email before pressing the buttons!