Burger King

I enjoy dipping my fries in the onion ring sauce. I am told that I have to pay for that sauce because I didn't order onion rings or chicken fingers. The receipt says "extra sauce". It is not "extra" as it is only one. What's the difference? If I enjoy it with fries and not onion rings. That "extra" is ridiculous and the answers I got when asked what the difference is also ridiculous. That Burger King needs every customer it can get!