Adobe Acrobat Pro DC OFFLINE Activation

Here is my issue:

I have numerous PCs that I am installing Adobe Acrobat Pro DC that are NOT connected to the internet, will NEVER be connected to the internet and can NEVER be connected to the internet. I purchased numerous copies of my software (on DVD) from a reputable large IT company. I have loaded the software onto my standalone machine(s) and I enter the serial number printed on the Adobe DC box. The software loads and then it asks me to activate. I can ONLY do the Offline activation. It brings me to the screen with the request code and gives me an web address of www.adobe.com/go/getactivated.

On another machine, I go to that web address and enter in the response code given to me on the offline machine. This has worked on 5 other installs. On two of the installs I get the error "Request Code invalid".  I have called 1-800-833-6687 three times and I have gotten responses of:

1. I have to connect to the internet one time. (This is not true as I have done this on other machines)
2. I have to download another install of the software. (This does not make sense, seeing as how I bought the DVD software)
3. I have to wait 72 hours to get another request code.

I have ensured that each time that  I entered in the code and gotten the Code invalid that I try to enter it at least 7 different times to ensure that I was not messing up characters or capitalization.

I am at my wits end with this awful customer support. I legitimately purchased software that I cannot use and is holding up work.

Would someone be able to help me to fix this issue on the TWO serial numbers that I am trying to activate so I can get some work done.

Thank you.

john