Client Query - I use credits, why are you sending me an invoice?

Client Query - I use credits, why are you sending me an invoice?

Question/Problem 

We have pre bought credits but have received an invoice, what is the invoice for?

Resolution/Solution 

This invoice is just for your records, if you download it from from your Admin portal you will see that there is nothing to pay as your credits will have been used to fund this with a 100% discount.