Hi Geti,
I just wanted to reassure you a little bit. I brought home a dendrobium a while ago and right away it lost 2 buds and one leaf went yellow. I panicked but after advice from here calmed down. Now the remaining 10 buds have opened. A few more leaves did turn yellow but I was reassured this was normal for older leaves. Anyhow, now it has bloomed for over 1 1/2 months and is doing great. As soon as your phal adjusts, as long as you follow this advice I'm sure it'll be fine!
Welcome to the forum!