Need help – Added code for diamond character but won’t accept change..

I looked up code for inserting diamond symbol/character as bullet in front of text but when I select “update” and check my website, it hasn’t changed. It has a ‘?’ of all things and I don’t want my customers to see a question mark where I am trying to highlight the services I offer. I have tried several times by: deleting ? in the HTML view and replace it with ♦ which is supposed to be the code for this character/symbol. Why is it not accepting my change?