I received a mail from you asking for my account data including the password - is it genuine?

No. We will never ever ask you to tell us your password.

This mail is from someone trying to steal and abuse your account. This kind of attack is called phishing.

How can I delete ~/.OldFiles ? It's eating my quota!

No, it isn't. That's just a snapshot of your home directory as of last night. It doesn't count towards your home quota.