When you accept a suggestion, you should get taken to the create quest screen, with the description your ally gave you preloaded. From there, you can save it to officially add it to your quest list. Which of those screens didn’t show up for you?
An error occurred while saving the commentDeirdre commented
I've just had the same thing happen, with one PowerUp and one BadGuy. I clicked the Accept button on both, and now they've disappeared. Please get them back - they were great suggestions!