Generate an appropriate username and password combination.
The username should be at least eight characters long and contain a mixture of letters and numbers, while the password should be at least eight characters long and contain a mixture of letters and symbols. For example, the username could be t@y17E7Ky7 and the password could be p@9VtH6nY.
An appropriate username and password combination is 'JonSmith123@example.com'.