Let me get this straight. You lost track of time. You were 30 minutes late in picking up your child. The child caregiver missed her lunch. She brought this point to your attention in what you say was a rude manner (to the point that it almost brought you to tears).
And most people have agreed with you that what what she did was wrong. I am sorry, but I am missing something here.
You do admit your responsibility, yet IMO, you gloss over it by honing in on the supposed rudeness of the child caregiver. While I tend to agree with Jim B., if you feel she was indeed rude, then write a letter to CCL and let them know. But address your rudeness in the letter and rude you were. This caregiver has a life too. You (in essence) contracted her for x hours with you child, yet you waltzed back 30 minutes late and I would be willing to bet that you didn't even think about her point of view when you realized you were late.
This one really falls under the umbrella of "Personal Responsibility". You failed to take it.
Life is not a journey to the grave with the intention of arriving safely in a pretty & well preserved body, BUT rather to SKID In BROADSIDE, completely used up, totally worn out, and SCREAMING "WOW---WHAT A RIDE!!"