Facebook is not being blocked like it should be.

This isn't the first time this has happened. But under parental controls. I have Facebook blocked. We'll you can still get on and use the full Facebook app. But it is blocking messenger that I do need instead. Under the parental control it says messaging apps will not be blocked but Facebook will be and it's the complete opposite.  I hope this gets fixed soon. My kids don't need to be on facbook. And it's been like this for about a month now. I also have family link but they know their way around that.  Please fix this ASAP.