Mailbox size limit

[#1]

I had an email saying my mailbox has gone over the 1Gb limit. I asked them if there is anyway of upgrading this and was told that there isn't. So there any way round this without having to delete hundreds of emails that I want to keep?

[#2]

Download them onto your pc
As an aside have you thought what would happen if the Plusnet system threw a wobbly and deleted them
I would never rely on an external server for emails I wanted to retain

[#3]

How do I download them?
Also when I log into my webmail there is nothing in there.
I have to have the otion to keep emails on the server ticked because of my mobile devises.
Interestingly when I go on the comparison sites they done seem to list mailbox size.

[#4]

So you don't need them on the server once they have been downloaded to your mobile devices so can remove the oldest ones from the server
How are you logging into webmail as you will be able to see them if you login via the correct mailbox which is in the format username+mailboxname

[#5]

Hi thanks for that. I am using Thunderbird and there is a server setting that says something like ' leave messages on server for x days'
Does this mean that if I set it to 7 days everything older than 7 days will now be deleted because if so I will use that to clear everything older than 7 days off the server which would save me manually deleting everything. And if this is the case how and when will it sync to get rid of the old stuff or is there something I need to do?
Thanks