Orssom on "No access information to back end of website"

Hi guys,
We recently had a website designed by a company and it appears they are no longer around. For the past 4 weeks I have tried contacting them via emails. phone, fax, sent emails also directly thru there website and no response.
The website went live on the 29/10 and it is not fully functional.
Issues: Cannot receive any emails directly thru the contact us page.
Shopping Cart is not allowing customers to check out once they have put there order through.
Our Online sales for the past 3 weeks have been Zero and it is starting to hurt business.
If someone can help me on how to access or point me in the direction of how to obtain our login / password information for the back end of the site would be greatly appreciated.

Website:

Regards Robin.