Hello Andy,
We apologize for the inconvenience caused, as per the description above, you are being directed to a purchase page when trying to export a PDF into Word document, Is that correct?
The record shows that you have an active subscription of Adobe PDFPack on your current Adobe ID, please try to access the services through the URL https://cloud.acrobat.com/convertpdf with your Adobe ID and password on a different browser like Chrome, or Firefox, or Safari and see if this makes any difference.
If you are using the free desktop version of Adobe Reader DC and getting the error message, then please sign out and sign back in with your Adobe ID and password in Reader and try to export the PDF file.
You may also refer to Troubleshooting Create PDF, Export PDF, Adobe Send, Fill & Sign … services(PDFPack or Document Cloud Services).
Let us know how it goes.
Regards,
Anand Sri.