Hi Timw,
Yes! you do have an active subscription of Adobe PDF Pack. Could you confirm how exactly you have been trying to access the service? Is it through the desktop application Adobe Reader DC or online via web browser https://cloud.acrobat.com/convertpdf ?
1- PDF Pack is an online service that you can use online via: https://cloud.acrobat.com/convertpdf
2- You can also use the services through free desktop version of Adobe Acrobat Reader DC: Adobe Acrobat Reader DC Install for all versions
3- “Sign In” using the email (Adobe ID) under which you have subscription registered.
4- For detailed description of how to use the PDF Pack service, you may refer to-How to Use Adobe PDF Pack
You may refer to the following link for any troubleshooting: Troubleshooting Create PDF, Export PDF, Adobe Send, Fill & Sign … services(PDFPack or Document Cloud Services).
Regards,
Akanchha