http 500 error- admin panel wont show up

Hi, I am a new user to wordpress. I downloaded it from my website builder (Creative motion design) because they have wordpress integraded into their build. I updated and installed a template from the site and got an email saying it installed correctly. Here is what the email said:
Your new WordPress site has been successfully set up at:

http://heimbruc32085.c4.cmdwebsites.com/blog

You can log in to the administrator account with the following information:

Username: cmbysarah
Password: The password you chose during the install.

We hope you enjoy your new site. Thanks!

However, the admin page is plain white/ wont load.

I have tried clearing the cache, and it gives me the http 500 error message on google chrome. Wont load on firefox or safari.

I really don’t know what to do, help?!