You got where you needed to be when you needed to be, and you want a full refund?

That is not going to happen. I'd say if you're lucky, you'll be reimbursed for the car seat, and given maybe a $100 gift card. But more likely a discount code.

If I had a full refund of my ticket for every time I had a rude agent, I'd never pay for a flight

Also, as jjclancy mentioned, IRROPS happen. I would never travel with the REQUIREMENT I arrive within 24 hours of my originally scheduled arrival, if I'm connecting internationally. My best advice is to give yourself a buffer. It also takes a lot of the stress out.