New prepaid Data plan for IPAD - cannot access with iPAD.

I have used ATT for years with iPads.  Just got a new iPad Air 4.  Set up the account online with my Mac.  I entered the IMEI and the CSN/EID of the iPad.  When the account and payment $$$ was confirmed, the CSN/EID looked completely different.  Tried to update the CSN/EID again, but the online app modified it again.

And I cannot login via the iPad.  I use the same ID / password I used through the browser on my Mac, and it gets rejected, saying it is the WRONG password?

The chat provide with the att/ipadlanding page has NO idea about iPads... pretty dumb configuration.

I am about to cancel the subscription and go with TMobile. 

Help!