Called my cell number twice in one day. No message.

It's legit, really Jill Stein's phone bankers. Some are better at it than others, that's why there's complaints.
https://m.reddit.com/r/jillstein/comments/50v ... ing_complaints/

Called asking for campaign contributions to Jill Stein. I said I will donate via the Green Party's website. I live on the east coast and the Green Party is on the east coast. They called at 8 pm. When they said 'good morning' it raised some red flags with me. I love the Green Party. I think Jill will be an excellent POTUS. But, unless I know the money I donate is going where ot should, it stays in my grasp. Sorry Jill. if it's all a big misunderstanding and someone can prove it. i will donate more than I had initially planned to this September. Peace and wellness to all who accept it.

That would make sense then because I've donated to Bernie and now Jill and received a call from this number but didn't answer and they left no message

Not sure who this is, but did not leave a message.  I have gotten a number of calls looking to donate since I did so to Sanders and Stein.  I donate via the website to my causes, so no ID and no message = BLOCK.