hosting co.. help!

Hi guys, First of all my apologies for posting this here.. however as I am running out of options, someone here may provide me some respite... How can/do I start legal proceedings against an Hosting provider?? I had registered a domain called www.greatanddear.com with 121host.net based in the UK but after a couple of months my site disappeared completely along with all the content.. Inspite of dozens of mail these guys simply dont respond... Is there anyway, I can sue these guys?? I can neither login to the admin section as I get an password denied error.. any suggestions?? thnx a bunch, sands..