How to prevent Facebook Messenger calls from popping up on my lock screen?

[FaxMachine]

I'm having trouble stopping facebook messenger calls from appearing on my Note 7's screen. Here's what I've tried:
- Disabled "show on lock screen" from central settings
- Disabled "show content on lock screen" from central settings
- Heck I've even complete disabled all notification from messenger in both the central settings menu and the app menu
- Turned on "do not disturb"

None of these work

The only thing that works is turning of wifi haha which is not an ideal solution.

Is there anyway to stop facebook call from randomly invading my phone's screen even while its locked?

Thankssss

 

[FaxMachine]

Anyone?

Surely somebody knows a solution to this.