tried to change site url and am locked out now

Greetings. I own the domain name lis101.com and am using WP as my CMS and host . I was told that I could change the URL of all the pages on the entire site from the ugly URL https://03d2fbf.netsolhost.com/WordPress/ to the lis101.com URL in the dashboard. So I backed up the database and made the change. Unfortunately, the site crashed and I am unable to log in to change it back. Whenever I try to login, it redirects the login and the page is not found. Anyone know how I can get back in and change the site back?