fast and furious 7

I got to 87% and can not go any farther. I have two cars that took 3 races to win, I only finished 2 races but the game gave me the cars and now the challenges do not show up on the map anymore. Can any one tell me how to complete the challenges and unlock the remaining challenges?

I have one achievement left to get, I need to bank a skill chain of 50k or more, I have come so close several times but always break it just before hitting 50k lol.

update. went to cloud saved games and completely redid entire game. still stuck at 87% and 2 cars not collected and 3 awards not received. what does it take to unlock last 3 rewards?