You might want to repot it into a bark mix, rather than moss. It's less likely to get moldy, and I've found that my phals do fine in bark.

Thanks Susan, is there a specific kind of bark that would need to be used?

What are your growing conditions and what zone are you in?
Sounds like the plant is being kept too damp and underlit. Could you provide more info.

Jane

I find it very odd your moss has become moldy. I grow lots of plants in moss which are kept moist if not almost wet all the time and have never seen any sign of mold. What kind of moss is this? Sphag or something else? Could you post a photo?

Kevin

I just use the same bark mix I use for my catts. It's more forgiving if you ever over water, I think.