I was given this houseplant 3 weeks ago. When I unwrapped it it was totally pot-bound, with roots coming out of the compost and it looked very unhappy. I took it back to the shop and was told that they only flower when potbound and was advised to keep it somewhere warm and light. Many of the leaves have since turned brown and crispy and most of the flowers have gone from red to purple and are dying fast. There is no sign of any infestation. Any comments/advice?