Yep. Big customers are great, if they accompany big contracts. If you’re getting raked over the coals, who cares how big the company is that’s doing it?
So here’s the lesson: if you let a customer use you as a doormat, they’ll continue to use you as a doormat. It’s only when you stand up and say: “cut the BS right now and fulfill your commitments” that you get respect… and make the sale.