my hotmail has been linked to facebook without my consent

Hi I wonder if someone can help me to resolve this issue

I created a hotmail account which is not the same account i used for Facebook

I look at my hotmail profile and the only service I am linked are Messenger and Skype.

Anyhow my account hotmail has been linked to my facebook and I am don't know what to do to unlink my hotmail from my facebook.

Many thanks