I just sent an email to support, and haven't heard back. And, yes I'm in the US. Here's an update. I have an
Air 2S that's also linked to someone else's account (bought from the same store). I was able to go through the connection guide and connect to the RC Pro no problem. While connected I went to profile>device management. It said it wasn't connected to an acct and gave me the option to bind it to mine. Then, I reconnected it's original controller through the connection guide, and under device mgmt it showed it was linked to that old acct.
So, I decided to try the
Mavic 3 again. Went through the connection guide, and was met with the attached photos. If you hit cancel on the binding screen it'll let you fly or connect up to 7 times. I found that number resets if you factory reset the RC Pro controller. Also, while I had the RC Pro connected to the
Mavic 3, I went into device mgmt, and it showed the acct that it's already link to (unlike the
Air 2S that did not).