Sending orders from certain retailers

How do you navigate the issue...

A customer puts in an order. You then go online and find the product. You purchase the product from 'Company X'.

Company X ships the product. The use their own cardboard box with their companies name on it. They also include an invoice inside the box, saying the exact amount they have sold the product for.

The customer didn't pay Company X, they used your own website to purchase the product. The customer sees the invoice from Company X and are confused and angered, because they have paid your website more for the product, and now know full well you have simply purchased the product from Company X.

What do you do here? How do you get round this issue?