I’m sending "failed to deliver" emails to contacts which I never heard of

Well this seems to be regular since one or two months now.
I got a contact list with +1000 contacts, never heard of them thought.
So it always says:



Delivery Status Notification (Failure)‏ postmaster​@mail.hotma​il.com

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

*** Email address is removed for privacy ***

Most times there is some attachment file I obviously don't want to open.

Also there are some quite suspicious ads on the hotmail homepage.

I already changed the password and reinstalled my os, but is it possible to delete all contacts and the connection to the messenger?



Sincerely, "someonewhoiskindapissedoff"