If you are getting notifications from VistaQuantum, then your Mac is infected with adware. VistaQuantum is adware for Mac.
VistaQuantum changes setting in your Mac. First, VistaQuantum installs a browser extension in your browser. Then, after VistaQuantum hijacks your browser, it modifies settings in the browser. For example, it changes the default home page, modifies search results, and displays unwanted pop-ups in your browser.