So I was in a regular Hell game today to meet a friend. He then gave me tal rasha’s armor. we then played a little bit together in game, doing magic finding. we met the council and they wound up killing us. we killed them and retrieved our bodies in game. then he left the game, and I left a few minutes later. I went into a few more of my own games, hell and nightmare. then I went into a random hell cow level made by someone else. it was then I realized that my damage was really bad, I opened my backpack and I saw that my tal rasha’s armor was gone?! and replaced with a white templar plate. I have no idea how it happened, and even if there was gear left on my body when I died, it would’ve shown up in game until I cleared enough space in inventory to pick up my body. However this was not the case because when we both died in game, I picked my body up and then proceeded to vendor about 8 rare items dropped from the council. I don’t know how, but my tal rasha’s armor changed to a white armor. I hope there’s something you can do.
D2, D2R, and D3 have no second by second logs so there are no tools for the CS folks to do any restorations.
Most likely you picked up a white armor and equipped it as part of your run to your corpse.
Losing items on death is rather common if you are not super careful.
You may want to read the official D2 site on it in detail.
http://classic.battle.net/diablo2exp/basics/characters.shtml
Or your friend gave you a duped armor to screw with you 
there is a method ingame where you can duplicate an item and after a couple games the item changes back tto he original in your case the white one ^^