The name of the mission you're trying to do is called "Uzy Money" and not "Uzy Rider". However, D-Ice's Pay-Phone Missions must be completed before you finish "The Exchange", which is the last storyline mission. In fact, due to a bug in the game, the Purple Nines will disappear after "The Exchange".
Hope that helps.
Actually, this is false. I completed The Exchange 2 days ago. Then I completed "Gripped!" and saved the 5 D-Ice Payphone Missions for the final 5 missions in the game. And I was able to get Purple Nines to spawn...
I am playing PS2 version on my PS3.
Not only did I reach 100% again (today), I obtained 7 proof vehicles and used the Crusher Glitch on 4 of them. So now I have the AP/EC Stretch, AP Cheetah, AP Bobcat, BP/DP Patriot, BP/DP Barracks OL, BP/FP Trashmaster, and BP/FP Securicar.