Remember, Facebook and the like don't actually delete everything when you tell it to. You must:

• Explicitly revoke consent to the use of your data. It's as simple as putting "I hereby revoke consent to the use of my data" in the body of the ticket or email.
• Explicitly invoke Article 17 of the GDPR (Right to Erasure). Again, it's as simple as plainly stating you are invoking it.
• State that you are severing yourself from the Terms of Service AND releasing them for any obligation they held as a result; regardless of any damages, perceived or otherwise.

Just a warning, if you are not a EU citizen, you can still invoke the GDPR, however, if they refuse to comply, you have no recourse.
Additionally, there is a strong likelihood they will want proof of your identity. This isn't so as much for malicious purposes as it is them wanting to confirm it is actually you doing this.