Usually, when a phal has sad wrinkled leaves, something is wrong with the roots. Very rarely will a phal ever be underwatered...they are like little cactus. What is easy is to overwater. When you repot an orchid, stop watering completely for about a week or two weeks. Best is two weeks. This allows broken roots to heal before you apply water. Also; it is important to place the newly potted plant in a shadowed area. They need to recover from "shocking" when you repot them. Some plants are more sensitive than others. Maybe if you could post a picture of the plant, it would help id the problem.