Fix Admin Login -- 2

Have an ecommerce site with Joomla and Virtuemart. Recently, and without any known cause, we lost the ability to log into the "administrator" backend of the site. An error was produced saying we don't have an account. We still have access to cPanel, file manager, sql database, etc. Hired a contractor to fix this, and the result is as follows: - All usernames and passwords in Joomla and Virtuemart SQL tables got reset to generic data. So no prior users can login. - Administrator login works for Joomla "Super User', but only allows "admin" permissions in Virtuemart. So we can't change any user info. -Trying to change user info on front-end account area leads to this error page: "500 - View not found [name, type, prefix]: user, html, usersView" Need someone to fix our login permissions and SQL tables. Possible a mismatch between Joomla and Virtuemart user tables. Unfortunately the previous contractor did not make or request a backup copy before his work. All tables were intact and users were in order prior to his work. He claims it had been hacked. We need to fix his "fix". PLEASE BE ENGLISH PROFICIENT and keep in mind I am in Pacific Time Zone in USA. Thank you.