why i (lv 100) did not give back shaymin

he asked for a pikachu with sertin ivs but i diddnt know that so we traded 2 days later he wanted it back so i offerd him othe pokemon he diddnt want them so i said ill give shaymin back i got to trade and he tried to trade me pikachu but he took my exp share off i said if i trade back shaymin give me my pikachu with my exp share i gave u then he said not unless u give me a certin berry i didnot have so i didnt give shaymin back untill today april 10th 2009 so thats the story

for more info pm me

All this over a simple Exp. Share.....

Well, Exp. Share is important for training pokemon Level 1-25.