If you are getting notifications from UnlimitedPixel, then your Mac is infected with adware. UnlimitedPixel is adware for Mac.
UnlimitedPixel changes setting in your Mac. First, UnlimitedPixel installs a browser extension in your browser. Then, after UnlimitedPixel 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.