Terrible workmanship

Terrible workmanship. I had to get my iPhone screen fixed. To which they agreed coming in just under the quotes I received from anywhere else. The screen was replaced but wow have I had everything go wrong. It freezes when it’s cold. It cracks and pops out of place and now it’s broken completely. They wrote me a receipt on a piece of paper and made me pay cash. What do we do about people like this?