It's very simple...
Open the Messenger app (on iPhone or Android)
Tap your profile picture
Select 'Sync Contacts'
and turn it off.
It may already be off - if this is the case then do nothing - your data and calls have not been logged - chuffed.
One user, Dylan McKay downloaded his Facebook data and found that from October 2016 to July 2017, the network had logged every single one of his calls. Facebook issued an official statement saying that the ‘feature’ was opt-in and offering instructions on how to switch off the constant surveillance of users’ phone calls.