I suggest you to go to your setting on your tumblr, it’s that round thing just beside your log out button. I don’t know what do you call it in English. Nut? Bolt? Then on your right handsight you will see a list of things; account, dashboard, notifications and apps. Choose the last one and delete the apps that you don’t want. I was hoping for some followers when I signed up to infinitefolowers and a prompt from ‘Lana del Rey’ asked me if I would give her permission to post on my behalf. I found her name of the list in my apps, deleted her and no one had posted anything on my behalf.. Good luck!