The tax imposed by this part shall not apply when the video programming services or direct-to-home satellite services are sold for resale. “For resale” means that the customer of the video programming service or direct-to-home satellite service provider purchases the services, sells those services to others, and is liable for the tax imposed by this part, or for the sales tax imposed by chapter 6 of this title, on its sales of those specific services. The commissioner is authorized and empowered to require the use of certificates of resale, or other satisfactory proof, as proof that any sale claimed to be a sale for resale is in fact a sale for resale. In cases where a customer purchases some services for resale and others for the customer's use and consumption, the seller shall separate the taxable and resale amounts on the bill, invoice, or statement provided to its customer.