What's wrong with my potted rozalea?

I got a rozalea for a gift 1 1/2 weeks ago and repotted in a bigger pot. 2 days ago the pretty light lavender flowers started to wilt, which I expected to happen, but also along with the healthy green leaves that are falling off their branches. I have it next to a window and I keep the soil moist but not dry,so what could I be doing wrong? It looks really sad!!!