Hey there,
You could do a WHOIS lookup to see where your domain name is hosted. And then contact that domain host to gain access to the domain. You should be the legal owner of your domain name and gain access to it.
Once you have access to your domain name you can then point it at different website hosting. You'd need to re-create your website on a different platform, I can recommend one.
Use a tool like
https://who.is/ to find out what your "registrar" is and then make contact with them.
Cheers,
Richard.