Exact same problem!

I've been trying to get this fixed for YEARS! Every few months I'll have the courage to call - again. 

About 45 minutes in, after speaking to multiple customer service reps, I'll get someone that finally trust that I'm not dumb and doing it wrong. They will forward me to merchant services, and they claim that in order to verify the account for a phone number change, a mailed postcard or email will be sent to verify. I write down the number of the support ticket and patiently wait.

Weeks go by.

I call up customer service to check in on my support ticket. The new rep will say there is not enough information on the ticket, and will need to start a new one. I explain my situation, they tell me it can be reset in account settings - "just go to your qbo account and click the gear icon"...I hang up the phone.

3 to 4 months go by and I get the courage to call customer support again. And here I am - searching google and finding this thread. Saddened by the reality that nobody at quickbooks customer support has the authority or power to rectify this situation. Otherwise there should be a person or two on here posting "it worked, thank you!"

Good luck!