I have bumped into a very annoying bug in skype.
My contacts started telling me that I am logged in all the time, so i logged in to my account by browsers and changed my password. But still the problem is not solved.
Then I tried the these,
Get all logged in device by typing
in you chat window to any contact, you will get reply as devices and ID of where else your account is signed in.
Sign out all other instances except the current one.
This will also stop push notifications on all other instances.