Laptop part not delivered

Hi<br> <br> I ordered a part from PartServe on the 16th September 2015 and I was told I will get it after 4 weeks, that turned to 4 months and I still don't have my part. I was sent the conformation that the ETA is for the 17th December 2015. I still don't have my part though I payed for it in Full. What does a person do to get service here???