I do experienced same with what you had. I am doing signatures, social media, twitter and even translation campaign just to earn money. But unfortunately, some of the projects i participated with did not give my reward. It is so frustrating and disappointing but later i realized that it is better to accept and move on because more blessings to come. Quitting is losing so better continue and work hard again but we need to be wise and smart in choosing the best bounty campaign to participate with.