@TomTresch I moved your post to this thread to keep the community organized.
It sounds like you may have more than one Google Play profile, or another Google Play account under an alternate email address.
The error message depicted in your second screenshot indicates that your Pandora Plus subscription was purchased from a different Google Play account. Unfortunately, our support team is unable to search for that using payment information, since they don't have full access to the Google Play billing system. I'd recommend making sure you're signed into your main Google Play profile.
Otherwise, you can reach out to Google Play directly, and they will be able to advise you using your payment information. +++++++++++++++++++++++++
An alternative option would be to cancel your current subscription through Google Play, and then resubscribe to Pandora Premium directly through the Pandora website.
If that sounds easier, let me know and I can get you in touch with someone from our support team to help out with that.
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