Doesn't the clip secure into nut? i.e. you need to push them into what they call the nut. What was the part number you bought? I think you need them both to work in conjunction with each other.
W716503 S300 :
https://www.ebay.com.au/itm/OEM-Genu...EAAOSw7RJeh4k6
W716350 S300:
https://www.ebay.com.au/itm/Ford-OEM...frcectupt=true