Bad mannered kid

My child broke a mug at this store and the lady (didn't get her name) told me I had to pay for it because she isntired of people with bad mannered kids. She is tired of goods that are damaged and they end up loosing out on incentives. I paid for a mug that I didn't need because according to her my child is bad mannered. The mug was on the edge of a table and fell, she didnt want to acknowledge that it was a mistake and insisted it was because I let my child play with a mug in her store. Simon tilled the mug and gave it to me. What am I supposed to do with a broken mug? What is the policy on goods damaged inside the store?