Phal flowers wilting and falling off, black on undersides of leaves

[JudyWilson]

I'd really appreciate any advice I can get with my new Mother's Day orchid. Within a day the flowers folded up, and they are falling off. The leaves have black edges on the undersides and black spots. I'm thinking it was overwatered, I took it out of the pot, removed about a quarter of the moss, tried to dry out the rest of the moss and then repotted. I didn't have any new moss so I used what I semi-dried out. Is there anything else I can do? Should I get new moss and start over? I have pics that I'm trying to figure out how to attach.
Thank you!