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Most of the roots look OK, although I can see one dead one accross the center the others appear to be OK as far as I can see.
Dropping of the lowest leaves, can sometimes be normal and they do tend to turn yellow before they drop. However it can also be a sign the plant is struggling. One with bad roots will reduce it's number of leaves, but they also loose leaves through age and as they grow new ones.
Flower buds blasting (dying without opening) is yet another thing which can be normal after a change in enviroment (from the nursary/shop to your home), but can also be a sign of problems.
So it's difficult to tell from your description and pictures if there is a problem or not.
If this was my plant what I would do is check the roots. It looks as thought the moss it's in is very dark and possibly broken down which could be a problem. Take it out the pot and gently prise away the moss to get a good look at the roots in the center.
If the roots are mostly firm when you gently grip them in your fingers then they are good. If they are hollow or mushy then they are bad. As I said above I can see one bad one, but if they are mostly bad then that is a problem. Mostly good then it should be fine.
It's possible to resuce if there are any good roots (sometimes even if there arn't but it's more difficult). Let us know if it looks like the roots are bad and we'll try and help with how to save it.
If the roots are mostly good, but the moss seems broken down (smelly, dark etc) then it will need fresh medium. Many growers here don't like moss and would pot in bark (including me) because it is difficult to avoid rotting of the roots if you are in a humid enviroment. Others love moss, but it depends on your watering style and enviroment.
It's best to get fresh medium from a good source.
www.repotme.com is meant to be good in the USA. There are other sources but some of the stuff sold in your non-specialist shops is not very good. Even stuff sold as orchid bark is often for terestrial orchids (which is not what you have). I don't live there so hopefully others can adise further on what is good or not.
It's best to check the roots sooner rather than later. If you do and decide it needs repotting it is possible to keep bare root for a while, but you need to soak the roots every day when there is no medium arround them. Either that or try and put back in the existing medium until you can get something new, but if it's 'sour' then it's best to make that as quick as possible.