How do I contact Facebook about potential fraud with my account?

I have gotten an email bill from Facebook and I don't know why since I did not sign up for "Ad Manager" (Which seems to be a system so you can put your advertisements on Facebook. But I do not arrange to use this feature).
I think  that maybe Facebook or someone else made a mistake or  worse, someone intentionally  hacked my account and  is having the  bill sent to me.
As far as I know, no money is being taken out of my  bank account since I have not signed up my bank account with Facebook. But what could happen is if I don't pay the bill (why should I?)  then Facebook might take action against me for not paying?  What should I do?  Just tell them that  someone is somehow using my account to have them send bills to me? How do I  reach Facebook? There is  no  link or  information on Facebook as to what to do in case of  account fraud like this?  
Depending on the answers I will provide more information or ask more questions

Daniel2020-09-20T19:12:52Z

Facebook wont know anything about it those Fraud Emails happen all the time they look to Steal peoples Account Information the Best thing to do is just Delete those Messages your Account is Fine