Normally when you receive an email notification but can not find the publication in your account it is being delivered to a different email address. To double check this please look at the bottom of the email notification you received. There will be a paragraph in gray letters that reads "this email was sent to" -- what is the email address next to it? Is that the email you usually sign in to Zinio.com with?
If the publisher/3rd party has a different email address for you, this may have created a second account at Zinio with the email they have. We can merge the Zinio accounts into one. We just need to know the two email addresses and for you to specify which one you want to keep as your Zinio login.