Fixing expired SSL Certificate

Hi. Thanks to everyone on the forum. Up until now, I've been able to remedy every problem I've encountered by digging through the forums.

Anyway, any help on this new issue would be appreciated. Whose responsibility is it to renew the security certificate? I've had many customers write in saying they were either worried about ordering from us because our security certificate had expired or were unable to access the secured portion of the site entirely.

When I visited my host's site, it says that they provide a shared SSL certificate and I have been hosting with them for about 3 years without this problem occurring. The problem is I'm left in the dark since when I call their phone numbers the past week it says the number is unavailable and I get no response to emails.

Any insight on how to fix this problem would be greatly appreciated. Here is my info:

website: https://www.mixi-bang.com
Zencart version: 1.3.8
host: sashbox.net

message when visiting secured area:
The certificate for this website has expired. You might be connecting to a website that is pretending to be "mixi-bang.com" which could put your confidential information at risk,

certificate information:
s17.securedview.com
Issued by: Equifax Secured Global eBusiness CA-1
Expired: monday, April 27, 2009 12:20:05 PM PT

renew of Shared SSL is your host responsibility .

is best to have your own Certificate rather then shared one. however, if your host is not responding to you . and they have failed to renew their certificate . i guess is time to look for better host .