I had a 400 sq ft stamped concrete patio installed at my house a couple weeks ago. I'm already getting some spalling, many chips all over and some flakes where the color has faded/flaked off. The felt paper between the patio and the house looks terrible and almost rotten and the steps are not straight nor level. Besides sloppy craftmanship could something have been wrong with the mix? I'm not sure if the contractor needs to tear it out or fix just the obvious problems. Thanks in advance!