Facebook has my phone number. I have never given facebook my phone number. The only reason I know that they have my phone number, is because a couple of years

Facebook has my phone number. I have never given facebook my phone number. The only reason I know that they have my phone number, is because a couple of years back they decided that getting me to enable two-factor auth would be much easier if they prefilled the phone number field with my phone number They probably got this phone number from the address books of any friend of mine with an android phone (as Android required accepting all permission request to use an app, until a couple of years ago), When I go download my data from Facebook, the data doesn't show that they have a phone number linked to my account Under GDPR this is unacceptable