Was your original site built using the Doteasy website creator? It sounds like your old website admin developed the site using a different program.
If you original site was not built using the Doteasy website creator you cannot edit it using this tool. You are pretty much stuck with editing the existing site with a text editor or your own website building program. You can also choose to re-create the site using their website creator which will allow you to make any changes through their tool. This will require you to build the website from scratch but it might be easier for you in the long term.
On a side note, to confirm who your current hosting service provider is, you can do a WHOIS lookup for your domain name. Type in google search "yourdomainname.com" WHOIS and it should come up with your domain WHOIS information.
For any specific questions, you might also want to contact Doteasy support.