Ecom Express — Product not received . Updated as delivered. Suspected fraudulence.

I have ordered an candes stabiliser for 5, 500 and it got delivered once properly bht defective so replaced it and the shipment was taken on time. This time the replacement delivery msg came with ecom express executive phone number and a pin number . I have not got any call and the update msg I got was the product got delivered to me. Truth is I was not even there on that said date and time . I have not shared my pin to anyone. Now struggling with amazon and ecom to get the product back. Such an embarrassing situation at office as I did it for office . Pls expedite and help me get my product soon.