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