Hi Maggi,
I too have had my ups and downs with
Epipactis gigantea, which is a bit embarrassing since I am supposed to know how to grow these 'weeds'. Not having any garden to speak of, my plants live in pots. I believe I have now discovered the secret of failure. Black pots heat up too much when the sun shines on them. The roots don't like it. So I now hide the pots behind a wooden frame, made of simple gravel board. There they stand in trays of water all through the year, and now they are thriving. Bletillas are grown in deep fish crates, with their pots covered with compost, again success at last. Maybe you'd like to try it one last time.