Professor wants my "non-funded" master's data
She never did any investment apart from giving her time


Whoa, there! That sounds like a significant investment, to me.  Indeed, it's hard to see what other investment you could reasonably expect her to make. She's not responsible for your funding; she can't do the work for you because it's supposed to be your master's project, leading to your degree, not hers.

Nonetheless, it is typical for an advisor to provide sufficient guidance intellectual contribution to the project that they could reasonably expect to be a co-author on most papers coming out of the project. This is joint work and it belongs as much to your collaborators as to you, even if you don't get along with your collaborators any more.

What does it cost you to hand over the material? Do you expect to benefit from it in some way that will be diminished by giving it to the professor? If it costs you little or nothing, it's hard to see any justification for not handing it over.  "I don't like her" is spite, not justification.  The main benefit that I see from handing it over is that you can expect to be a co-author of any paper that results directly from the work you have done. And, if you do hand over the data, you should make this a condition.

You should also consider the impact of your decision on your future career. If you intend to leave academia then it's probably minimal: you're unlikely to be asking for a reference from this professor and it's unlikely you'll have any interaction with her in the future. However, if you intend to stay in academia, you need to think carefully about this. People's perceptions of your actions will depend very much on who they think was at fault. If, for example, your professor has a reputation of being difficult, maybe you gain sympathy from the community. However, if she has a reputation of being reasonable, trustworthy and easy to work with, there's the danger that you acquire the reputation of being difficult to work with, falling out and torpedoing projects.