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