Linkia's are very sensitive to change (salinity, temp., ect.). Any drastic changes will start them on a downward spiral... that's almost always fatal. I've heard that very long drip acclimations, on the order of 10+ hours, are preferred. The timeframe you've laid out is fairly common for them to show signs of stress.

In addition, no one knows exactly what they eat. It's thought that many starve from the time they're removed from the ocean until they reach our tanks. In such a weakened condition they are even less able to handle the stress of acclimation.

Unfortunately, it is probably not going to recover and should be removed and disposed of.

Sorry for your loss,
Tom