If you log out of the dashboard, select “Forgot your email” and enter your domain, Cloudflare will email the account holder with details.
If you don’t receive the email you will have to add the domain to another Cloudflare account, set the new allocated nameservers at your registrar and set up the DNS in the new account. Some of your DNS records are as shown here… https://cf.sjr.org.uk/tools/check?b716d29b25f24710898f69d80ac1dc39#dns