try this way for the contacts that cant delete:
0)Log off from WLM and butterfly messenger,outlook.com
1)log in from skype with your msn e-mail
2)it will show you all your contacts include msn contacts and skype contacts
3)delete the msn contacts that have problem
4)log off skype and wait 24 hours
5)log in again from butterfly messenger to check if the ''problematic contacts'' have been deleted. if so,add them again.
make sure that the other contact add you also using butterfly messenger.
make sure that the other contact do the above also!