Cannot activate Peacock benefit — PPG_0017, requesting entitlement reset

Activating the Peacock benefit included with my Xfinity service fails
every time with:

"Your Xfinity account is already linked to another Peacock account."
Error: PPG_0017_4215b35

On the Xfinity side the offer still shows as available and prompts me
to activate. The failure happens at the handoff to Peacock.

What I've already ruled out:

- No prior paid Peacock subscription, through Xfinity or directly. I
  created a free login once, years ago, and never subscribed.
- I used the "Here's How to Find It" lookup linked in the error banner.
  It returns no account at all.
- Checked my alternate email addresses. No Peacock account under any
  of them.
- No recent move or service transfer, so this isn't a 72-hour
  propagation delay.

Since Peacock's own lookup finds nothing, I don't think there is a real
Peacock account holding this link. It looks like an orphaned entitlement
record that never released.

I'm asking for an entitlement reset on the Peacock offer for my account
so the activation token clears. To save us both a round trip: I'm not
looking to be walked through the activation steps again, and I'd prefer
not to create a throwaway account under a different email if the record
can be cleared properly.

Peacock's support channel is an automated agent and I haven't been able
to reach a person there, which is why I'm starting here. Happy to send
account details by Direct Message.