Getting error message saying cameras are already connected to another account

I just bought the Blink outdoor 3 camera system (used) from a family friend.After creating my acct I tried to sync the module but received the error msg that it was connected already to another account.What exactly would I needa do in order to get it released from their account? Not sure what u would need but if anything at all I figured the serial # & such so here is all the info thats listed on it:

Model: BSM00300U
Dsn: G8T1-LN00-0402-5C4G
Mac: 40:a9:cf:42:d9:33
Fcc ID: 2AF77-H1621502
Ic: 20741-H1621502

Many before you with the same problem. Enjoy the reading!