Package still pending clearance for 3 months

I have been trying to get my parcel for 3 months going on the 4th month now with no word about my package whereabouts from Fedex as they called me and promised to investigate my claims but until today nothing has been done. I am really at my wits end with this and cannot understand why it is so difficult to release from parcel. I need to know what is going on! Fedex is not acting like a professional courier company that they claim to be.