Can't sign into free Peacock account

I received an offer for a free Peacock Premium account through my Xfinity account.  I already had a Peacock Premium account, so I cancelled that and waited for it to run out.  (I know it has run out, because I logged in and wasn't able to watch things any more.)  But when I clicked the link I received from Xfinity to activate my free Peacock account, and entered my existing Peacock email and password, I got the message "We were unable to link Peacock to your account. You may already have Peacock Premium."  What do I need to do??