Happy that you joined us, I am sure that you will get all the help you need to rescue your plant.
You did not show us where you are located, this would help us to better advise on the best kind of potting medium for your conditions. I live in the Tropics and grow outdoors year round. The largest part of my collection is Dendrobium, and they are potted in a mix of Leca and charcoal. That works wellfor me.

@ Yew, Pindar and others who responded. The Spike and leaves look like a Den, but the Psbs. are so short and fat that I am a little puzzled. What kind of Den. do you think it is?