Window Regulator USA

Review: I sent my window regulator from a Mercedes G500 to them in October of 2013 for them to repair. I spoke with them on the phone before and after I sent the part and have a delivery receipt from the postal service to verify they received the part. I have not been able to reach them via phone, e-mail or letter mail since I last spoke with them after they got the part. The window regulator in question is a $1650 part and is essential for the window to work. I have no idea what's going on and need resolution on this matter immediately.Desired Settlement: I want my part back. If they fixed it, I will pay for the service. If they haven't repaired the part I want it back and they have to pay to send it to me as I paid to send it to them. I have no idea what else to do to resolve this issue.