Paid for 1 year subscription. Still getting advertisements. Nothing changed.
Put this in the troubleshooting forum and you're more likely to get help.
Have you gone through your options in the Help Center? They have a section for troubleshooting Duolingo Plus in there. To find it without the above link, hover over your username in the blue bar at the top of the screen (desktop version). A menu will drop down. From the menu, select "Help".
If you want a refund, but have gotten stuck in a loop of auto replies, please make sure you've submitted your ticket as a purchase issue via the bug report form. If you submit it as a bug or other issue, the sales department won't see the ticket. The bug report button is located at the very bottom of the Help Center page.