Shocking Courier Service

I was notified of a delivery to me by Buffalo, dispatched on the 21st December. sadly the driver delivered it to the incorrect address! it was signed for by the recipient. To this day i have been contacting Buffalo with no satisfaction. I have been told it has been relocated and will be delivered but seems never to arrive. I cannot contact anyone as the numbers given for communication are not available as the message remains FULL? The employee who was trying to assist unsuccessfully is now not at work and passed my number to a colleague but as yet I have had no call from their offices. This service is shocking. I have asked who the sender is but still no response from the company!