Repotted Phal

[Possum-Pie]

I inherited a medium size Phal. from someone who was on the way to killing it. I unpotted it, and found degraded media and dead roots. There were 3 healthy ones, and I pruned the dead roots and repotted it in bark. I didn't have a small pot, so used one I knew was too big. it immediately put out two new small leaves, but the leaves stopped growing and the single large original leaf got leathery. Finally, after two months, I decided to give one last shot at saving it. Pulling it out, there were 3 dead roots and 2 live ones. I'm not sure what I did that was wrong, I cleaned the roots, cut off the dead roots, and am going to repot in a smaller pot. Any suggestions?