Hello again, I would remove the ray from the tank and euthanize it (freeze it).
When you are ready to try again prep a tank without agressive fish, and sand or barebottom, but not gravel, JMO
I have gotten many fish and rays shipped to me, not all made it, that is a risk you have to be willing to take, if not, you can stick to local available stock. You can always place a special order with a LFS, if you trust them but then you have to deal with higher prices.
Most shippers guarantee live arrival, you got that, what happens afterwards is up to you, again, there could have been so many bad things happening to that box while it was traveling that you cannot blame the shipper, was it properly packed, was it what you ordered, did it get there on time, was it visually unhealthy? All of these are shipper issues, but anyhting else is not. Again JMO.
I have and will again ordered from TFD (by the way, no one said they are the sellers), check my post on their section, they were very good with me.
Rod