Alienware 17 Memory Upgrade Issue

Dell seems to have a problem finding an internal part number for the DDR4 SODIMM 2400T memory for upgrading an Alienware 17 R4 Laptop. The part number showing up on the website upgrade page is incorrect. My order was sent to me containing a PC3 1600Mhz  type memory (Standard DIMM and DDR3) . This is completely wrong. When I called Alienware support i get nowhere. I gave them the manufacture part number (SK Hynix HMA81G6AFRN8N) right from my laptop and they still cant find anything. Alienware Tech support doesn't know any part numbers and sales wants to send me the wrong part again. I am totally frustrated with Dell at this point and am tired of long phone calls that get me nowhere. There ability to find information internally is terrible. Any help would be appreciated at this point.