Fedex Overpriced Invoices

This will be the last time I ever use Fedex and I'll definately do my best to inform everyone around me to never use their services. For the past 2 weeks I've been trying to get a sample that was sent to me from China, I tell these Fedex Agents the shoes sent to me is a sample and a replica the shoes are not for commercial use and that everything in the box was not original. Fedex issued me with a R4800 bill even after I gave them my bank details to show them I did not buy the item. I was in email conversations for an entire week explaining to these people that the item was sent to me to promote and they were looking for every reason to for me to pay more. 1st they sent me a Invoice with the amount of R580 and after I paid the invoice they opened the package to look for the value of the shoes. I dont know why the box was opened in the 1st place. And after they opened the box they valued the shoes at R4800 and sent me another invoice after I told them the shoes were replicas... NEVER again will I use FEDEX *** services again. I actually feel like **** for using their services just to receive these stupid shoes. This is the 2nd time I had to deal with them last time I just let it go. They're bullies