I understand how you feel when something isn't working the way you need it to, @mjm0027.
I know that the Undo Reconciliation feature for a regular QuickBooks Online account is essentials for your business needs. I hear you and guide you sort this out.
First off, you're unable to change the beginning and ending balance of your statements once your account's reconciliation is closed. You can only manually change the Reconciliation status of your reconciled transactions to fix the beginning balance of your next reconciliation.
Now to fix this, I'd recommend contacting your accountant. He/she can help undo the reconciliation of your accounts with the help of his/her QuickBooks Online Accountant account. He/she can also help and guide you so you can properly reconcile your account.
Lastly, I've also added a couple of articles below that'll help you handle your account's reconciliation in the future:
If there's anything else that I can help you with, please let me know in the comment section down below. I'll be always around ready to help.
