You should not have to buy a third-party service just to change the primary admin.

The only real solution is to call Intuit and let the rep walk you through the process step-by-step.  Please note it will take hours.  Do not submit any documentation until you are on the phone with the rep - otherwise the Inuit employees always conveniently 'lose' them and/or claim that never received anything.  It took our CEO 2-3 hours on the phone just to get Intuit to change our primary admin to him.  This was our CEO - who certainly had more important things to do.  Good luck and grab some lunch given how long the process takes.