First of all, you should send the plant to me as soon as possible.
Secondly, it sounds like there might be a problem with the roots. I'd take it out of the pot and see what is going on. It should be in as small a pot as possible but lets worry about that later, check the roots and get back to us. There are others here with more experience than me and everyone here is always willing to help.
Pictures are always a big help, if you can, upload some of plant as it is now, and out of pot showing the roots.
Al