QuickBooks has marked invoices as paid when they haven’t been and I can’t undo do it, anyone else had this?

It’s marked invoices as paid and I can’t undo this, it’s like it’s linked the invoices to a transaction that doesn’t exist so I don’t know how it’s done it. This software has been awful! Constant crashes and bugs and the app is so bad too. Please can someone help as QuickBooks just refer me to “backend” team and I never hear from them again