What is your media ?. you could use a liquid seaweed extract to grow the roots. you will have to add 2 ml to 1 litre of water and dunk the plants for about 10 minutes. repeat this treatment once a fortnight and your phals roots would grow back.
another trick i heard which i have not tried is mix honey in warm water and allow it to cool down a bit and dunk the plant in that. honey is a natural antiseptic and would hep the plant to grow roots without any infection
heard some negatives about using rooting hormone powders for orchids and I have not tried using rooting hormone
try it and let me know how it goes. I recently bought liquid sea weed extract online and product is quite good. let me know if you want the source