Terrible service

DHL has invoiced the wrong account. I bought parts from a supplier in China in my personal capacity. My supplier send the goods to me via DHL. DHL took it upon itself to invoice the company I work for and not me personally. I am now trying to rectify there error. Phoning DHL has been a really frustrating experience. I have been passed from department to department. Always with the comment "not my department" The customer care department is the worst. I was passed around DHL to 4 different departments. My question is why have a "customer care" department if they don't care about the customer? How do I get an answer out of DHL?