Problem with hosting company

[bomberman]

Hi Guys

I have a small basic website for a local charity that I look after (for free). I have used a company for some years now to host the site, however since last Wednesday I have been unable to send and receive emails using the domain name. I have written, faxed and tried to telephone them to resolve the issues to no avail as I have no response. The website is still up and running only the email is playing up. I am unable to send and receive emails via the domain name, as the address is not recognised. I have paid the subs for the domain name and for them to host the site. They posted a note some days ago stating that e-mails will be down for an hour some days ago.

Any advice would be appreciated.

Cheers

Bomberman

Message after trying to send and receive emails:

User unknown; rejecting (in reply to RCPT TO command)