Atrocious service!!!

My item was calculated at an incorrect value by fedex despite the shipper sending them an updated invoice. I have sent them the updated invoice which they should calculate the invoice on that I received from my shipper and I’m getting no response from ANYONE AT FEDEX. Customer service keeps redirecting my call to customs clearance (Wayne Snyman, Clyde Francis, Tristan, Tesha Botha) but they do not answer their calls at all!!!