How to claim back money given to a colleague to invest in stocks?

A colleague told us that she will put our money in stocks, assured us that we will be receiving a certain amount of earnings every month. But 4 months already passed, I did not receive anything.

She is refusing to give me a cheque for my principal money. Is it possible to report her using the screenshots of messages we had? Or can a written agreement be made?

If so, where can I have it done? And if I want it to be notarized, what are the requirements for notarization?

I want to know if the notarized agreement can be used legally to report her.

Thank you