When's the last time you did something and felt cheated or like it was a waste afterward? Do you need validation?

My 7 year old and another girl recently got caught stealing from a kid in her homeschool group. She kept lying about it even after the other girl fessed up. I took away her iPod for a month. She wants it back "just for a few days" because she's super sick with the flu and I said no way. Her dad thinks I'm being mean and I should give it back. He argues that kids will be kids and she didn't steal anything valuable anyway (because she got caught...)  I'm sorry that she's sick but I feel like this lesson is way more important than her feelings right now. Am I being too harsh? Validate me, tqc.