I paid for a one month subscription so I could combine 10 pdf pages into one document. I can not access combine. I hit add, it does not say open, and I get a blank web page.
As per the description above, you are not able to combine PDF files as getting a blank web page, Is that correct?
The record shows that you have an active subscription of Adobe PDFPack on your current Adobe ID. You can combine up to 12 file at once to PDF. If you need to combine more files, combine them in batches of 12 or fewer to PDF, and then combine those PDF files.
Please try to combine the PDF files on a different browser like Chrome, or Firefox, or Safari through the URL http://cloud.acrobat.com/combinepdf with your crrent Adobe ID and password and see if this brings any changes.
You can also use the free desktop version of Adobe Reader DC to access the services of Adobe PDFPack, just "Sign-in" in Adobe Reader DC with your current Adobe ID and password. To download the Reader DC, use the URL Adobe - Adobe Acrobat Reader DC Distribution
For more troubleshooting, you may refer to Troubleshooting Create PDF, Export PDF, Adobe Send, Fill & Sign … services(PDFPack or Document Cloud...
Let us know how it goes.