But, connecting the RC2 to an iPad is not simple. You need a USB-C to HDMI cable, then an HDMI capture card for connecting to the iPad (if I remember correctly), running a capture App on the iPad to show the video feed.
I gave up and bought an...
Clarify.
Sounds like you have it bound to your account (since you've been using it), now you sold it and the new owner is saying it's bound to another account.
I.e. you have to go into the DJI Fly app and remove the drone from your account so...