We might have guessed it would happen sometime. When Wi-Surf became Clear Communications the old web site was still on the net. Most of the information on it was out of date though.
The only part that was useful to us was the webmail client because that was the way we could send mail via our Wi-Surf email addresses. The incoming pop3 server could still be accessed via Outlook (Express), Thunderbird or other email client. Now the web site is down and so of course is the mail server. So we can neither send nor receive mail via our Wi-Surf email addresses.
In my case the answer is relatively simple. I own the domain thewilliamsons.me.uk which I use for all my emails. Previously any mail sent to firstname.lastname@example.org was redirected to my Wi-Surf account and then picked up via the Wi-Surf pop3 server. So for now I am having my mail redirected to my Bigastro account and I am picking it up via their pop3 server instead.
Of course any mail sent to me between yesterday afternoon and this morning will still be sitting on the Wi-Surf server! Goodness knows when I will be able to access that.