Permanently remove facetime from Dock

My facetime app constantly reappears in the "recent items" section of my dock. I do not use facetime. Ever. But everytime I log into my computer, there it is with its notification flag. I have clicked "remove from Dock" and it just reappears. I do want to still be able to see my recent items that I am actually using, so unchecking the "Show recent items" box in system preferences isn't an option. I do not open facetime, I do not use it, the ONLY time it ever gets clicked on is when I right click to remove it from my dock.