This question already has an answer here:
I just got my PhD 2 weeks ago. Last April a professor offered me a position on her team pending a certain project's acceptance.
The project got accepted in July, and we had agreed that I would start work around the beginning of December. Since September I sent 3 emails asking about signing an actual contract. I was always told that we could proceed at any time, but she never got back to me when I expressed my desire to do so.
Two days before my PhD defense she suddenly asked me to start the employment procedures, which take around 3 weeks. While all this was happening she also asked me to begin work on some minor aspects of the project, which I did without compensation, simply out of a desire to maintain a positive relationship with her.
However, having been delayed to sign a contract for 3 months I was unsure as to her intentions and applied to a few other opportunities. I have received two much better offers and I'm not sure how to proceed.
I already discussed my situation to her on the phone and she was not happy with me at all. She said that I have already committed to working with her (even though I haven't signed a contract).
I really don't want to burn any bridges, but the other offers are simply better. What am I risking by refusing her and moving on those other opportunities? Is there a way of doing so without offending?