As I understand from the description above, you are getting a message to purchase/subscribe again when you try to edit a PDF form, Is that correct?
The record shows that you are subscribed to Adobe PDFPack with your Adobe ID. You cannot edit PDF files with Adobe PDF Pack. You need Acrobat DC to edit PDF files. See Adobe Acrobat Pro DC: PDF converter, convert PDFs from anywhere.
With Adobe PDFPack How to Use Adobe PDF Pack you can easily create, combine, sign, and send PDF files online. You can also convert PDF files into editable Word or Excel files.
You can use the services of Adobe PDF pack through the free desktop version of Adobe Reader, sign in with your Adobe ID and password in Adobe Reader, to download Adobe Reader Adobe - Adobe Acrobat Reader DC Distribution Link: https://get.adobe.com/reader/enterprise/
If you have installed the Acrobat, please sign out and uninstall it, and install Reader to use the PDFpack services.
Hope this helps, and keep us posted in case you need further assistance.