A payment is being applied in error to invoices as soon as we create them , how can I correct this?

Hello childtrophies, thanks for reaching out to the QuickBooks Community today

This usually means that the setting to automatically apply credit is enabled. When enabled, any unapplied payments or credits will be applied to the next invoice created for the same customer.

You can manage this setting by going to the Gear > Account & settings > Advanced (Take me there) > Automation > Toggle the slider to enable/disable. 

For any payments that have been applied incorrectly, open the invoice payment and select More on the toolbar and Delete. 

Thanks again for contacting Intuit QuickBooks support on the Community. We'll be around if you have any further questions!