Login with proxy's on webbased mail service

I need a script what is running on a linux webserver, the programming language doesn’t matter. It has to login with different socks 4/5 proxy servers to a webbased email site. Their it has to login (I have the usernames and passwords in a mysql DB) Then it has to compose a new e-mail with a text and subject from the database And send it to some contacts. Then sign out on the website and sign in again with a new proxy and another username and password from the DB. It would be nice if you can sign in at the same time with different proxy’s.