Like Lazer has implied. the issue in terms of your equipment very likely comes from your blade and not your rubbers. The Rakza 7 Soft is a rubber that is known for generating good amounts of spin easily and being excellent at blocking, so that would actually be one of the first rubbers I would recommend to anyone who has issues with spin regardless of their blade, if you were not using R7S already. The Mazunov blade however, is a very thick thus stiff blade so it requires a high level / advanced technique in order to generate spin easily, while it would be much easier for beginners / intermediate players to generate spin with a flexible blade like say a Butterfly Primorac OFF-. This leads me to think that the issue you're facing is not just with your blade, but mostly with technique.
Could you tell us how long you've been playing? In what setting: club, home, school, work...? If you're being coached. Finally, what blade and rubbers were you using before your Mazunov and Rakza 7 Soft? This will help us assess your issue better and answer it accurately.