Cannot Access Membership Benifits

When I attempt to access my Xfinity Membership Benefits I get an error saying "Sorry, only primary account holders are eligible to redeem benefits".  I am the only the person who uses this service and this is the only account associated with my Xfinity service, so I should be the primary account holder.  Why can I not access Membership Benefits?  

According to the tier levels I should be a Diamond member, as I have had Xfinity service for over 10 years.  I have received email stating I am eligible for Peacock Premium at no extra cost, but the link just takes me to the Membership Benefits page where I get the same "Sorry, only primary account holders are eligible to redeem benefits" error.