Matchday stores your display name, your phone number, the team you support, whether you confirmed you are 18 or over, and whether you agreed to hear from us again. You can add an email address, but you do not have to. Nothing else.
Your phone number is required for two reasons: it is how we reach you if you win, and it is how we keep one person from entering the leaderboard several times. It is never shown to other fans and never passed to the sponsor.
Agreeing to hear from us again is a separate tick and is entirely optional. You can play, and win, without it.
To have your data deleted, ask any Matchday steward at the ground.