Is there a way to reconcile an invoice that has an outstanding balance that hasn't and won't be paid? Is this a case where I should delete or void a transaction?
It's good you're reaching out to find out how to deal with a transaction to make sure your books are clean. I'll be happy to share more information about this so you can get back to doing what you love.
Based on what you've described, I recommend writing off the transaction as bad debt. Bad debt means a customer owes you money but you can't collect it. When invoices you send in QuickBooks become uncollectible, you need to record them as a bad debt and write them off. This ensures your accounts receivable and net income stay up-to-date. There's a helpful article which shows you how to do this. Check it out using this link: Write off bad debt in QuickBooks Online.
Before following the steps in the article, I recommend checking your Chart of Accounts to see if you have a Bad debts account or an Expense for bad debts account. If you have either of these accounts, you can skip to step 3 in the article. If not you'll have to follow all the outlined steps.
Give this a try and if you have questions, I recommend contacting our support team using this link.