Your call to 'help' likely wasn't actually to Apple, that started you in wrong direction.
The problematic situation reeks of Scam. Should've bailed on that before now.
Force quit your browser, restart with shift key held, clear cookies and history.
There's several pages with bits inside; examples of issues, some like you've got.
• Phony "tech support" / "ransomware" popups and web pages | Apple Community
https://discussions.apple.com/docs/DOC-8071
• Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support
https://support.apple.com/HT204759
• How to remove the after-effects of adware - Mac Malware Removal Help & Support - MWB Forums
https://forums.malwarebytes.com/topic/236261-how-to-remove-the-after-effects-of-adware/
• How to install adware - Apple Community
https://discussions.apple.com/docs/DOC-7471
• About pop-up ads and windows in Safari - Apple Support
https://support.apple.com/en-us/HT203987
"Check your Applications folder to see if you have any apps that you didn’t expect and uninstall them.
You can also check the Extensions tab in Safari preferences to check if you installed any unnecessary
extensions that you'd prefer to turn off. "
There are tons of helpful things, however to become & stay proactive
on the lookout for issues; be cautious. Bad-ware can affect your mac if
you happen to carelessly visit odd sites and take unnecessary chances.
{For you to have a Mac computer, & maybe not newest macOS with safe
guards built-in; using that with a bit of uncommon sense, has shades of
PC windows-user thinking. ~ Even there, they've come a long way.}
Take care & good luck!🐌|🌻|🐢
