He must be the boss

You must refer the invoice error to the Finance Department

This must be done today

You should have told us

I am sorry about the mixup

The Finance Department should know the answer

We can't help with third-party claims

I'll help you with this

The confusion is regretted

It was unfortunate that we were not aware of this issue

This is within the Finance Department's competence

Any assistance you need will be happily supplied

He is presumably the decision maker in this instance

This needs to be done urgently

It is not within our ability to provide assistance of this nature

The Finance Department is in a position to help with any queries concerning invoices