You would need to ask your TA to do the online checkin for you then. You can't do that over the phone. Also, that's how you can prebook Palo and excursions. A good TA should do that for you if you ask them to.
They really should have another option, because there are a lot of people that would be in that situation. My dad went on a cruise a while back and had the same problem. I did it for him on my computer.
GET UP TO A $1000 SHIPBOARD CREDIT AND AN EXCLUSIVE GIFT!
If you make your Disney Cruise Line reservation with Dreams Unlimited Travel you’ll receive these incredible shipboard credits to spend on your cruise!