Per Ars Technica’s story, call and SMS metadata was found in an archive of personal information collected by Facebook (any user can request a download of their own data to peruse) in their tests. Even after purging their contacts info, the archive still displayed this metadata, which means that Facebook likely isn’t deleting that information off its servers when you ask it to.
Facebook noted in a blog post that when you sign up for Messenger or Facebook Lite on Android, or log into Messenger on an Android device, you’re asked to grant permission to continuously upload your contacts’ info, as well as call and text history. So, technically, Facebook is off the hook in this instance, because users would most likely have opted in.
The obvious problem here is that most people probably don’t know that Facebook is collecting this data, and depending on how long you’ve been using the social network’s apps on Android, it’s hard to figure out if you opted in to allow this. The same functionality isn’t allowed on iOS, so iPhone users haven’t been subject to this particular data collection exercise.
https://thenextweb.com/facebook/2018/03/26/facebook-denies-scraping-call-sms-history-android-devices-without-permission/