==== 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.