Hi, Pastor. The reason your invoice appears as paid is likely because QuickBooks is set to automatically apply available credits or unapplied payments to new invoices. If there was a prior overpayment or unapplied cash in your account history, the system automatically linked it to this job to keep your books balanced.
To start over, you can either void or delete the invoice. Voiding cancels the balance and sets the value to zero while maintaining a record for your reports. On the other hand, deleting the transaction completely removes it from the record.
To do either, simply navigate to Get Paid, click Invoices, and select Void or Delete from the Action menu for that specific invoice.

To prevent payments from auto-applying, make sure to disable the Automatically apply credits before creating your next invoice.
Please know that you can always ask questions about QuickBooks or other product-related issues in the Community space. I'd be delighted to assist you further.