When you're at least level 10 you can go to cece's salon in Harlem and pay one diamond per collectible that you're having a hard time finding by just clicking on the random things that you get collectibles from if there's multiple quests that you need to get collectibles for & the first time you ask her for a collectible and she isn't offering the one that you want for the specific quest you're trying to finish you can decline it and then do it until she offers the specific collectible that you're trying to get for that specific quest that you're trying to complete