BobRay sounds like he's got your question covered, but I will add a few thoughts to your original post:
1) If you're attempting to overwrite the admin account's password in phpmyadmin don't forget to use the MD5 function, or visit this article:
https://docs.modx.com/revolution/2.x/administering-your-site/security/troubleshooting-security/resetting-a-user-password-manually
2) If you deleted all the files (except the mandatory modx files: index.php, config.core.php) from public_html, this likely points to a case where MODx may have been "hardened", which is where the core MODx folder may not reside in the public_html folder (to make the website more secure), and the cache folder sits inside the core folder. If none of the folders on the server seem to be named in some derivation of the word "core" or "modx", try looking for a folder that has some or all of the following sub-folders outside of the public_html directory: cache, components, config, docs, error, export, import, lexicon, model, packages, xpdo - a folder with all of these sub-folders might very well be your modx core folder. If this is indeed your core modx folder, refer to BobRay's suggestion in #3 of his post.
3) This may sound silly, but if you've never logged into the cPanel prior to this incident, also double check that the server your logging into is actually the server that is delivering the website. Since the URL you would have used to log into MODx is tied directly to the domain, make sure that the domain is pointing to the server you are logging into.
Hope some of that helps! If neither BobRay or myself have solved your problem, maybe give us a little more information about what you've found out so far and maybe we can help you figure out what is going on
