Delta Pilar Spray Assembly - Pull-Down in Stainless

Delta faucet trying to install new Ro5321rb faucet nozzle. Old one pulled out new one won't go in. Been at this for hours unit arrived without instructions. Thanks delta. Going to the hardware store to buy a new non-delta faucet and toss this one where it belongs the trash. To bad it worked for about a year in a second home and it looks great. I. Ought it because of the delta name. I think I will try a cheaper unit like in my rentals that last for years and can be repaired easily.