How do I change invoice starting date? With the new system invoices reverted back to 0001. Customer service said it would start doing this next invoice. Didnt work

Thanks for bringing this concern to my attention, thehrmaximizer. 
 

I know how significant the invoice numbers are to manage and track your transactions easily in QuickBooks Online (QBO). No worries, I've got you covered.

Since you already tried manually inputting the invoice number, but the next invoices didn't follow. Let's perform some troubleshooting steps to see whether the issue is within your browser. It could be due to a cache-induced browser that affects the program's performance. 

First, open your QBO account in an incognito window or private browser Based on your browser type, please refer to the keyboard shortcuts below:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

Then, open an invoice and manually input the desired invoice number. Create a new one, then see if the invoice number follows the previous number you created. 

If this works, you can clear your browser's cache to start a new slate. 

In case you want to personalize and adjust your invoices and other sales forms, you can check this article for more details: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Additionally, you can record the invoice payment you received from your customers to match it to the invoice in your QBO account to balance it in your account. 

Keep me posted if you need further assistance managing your invoice or any inquiries related to QuickBooks. I'll be here to help you to the best that I can. Have a nice day ahead!