Levi's Mall of Africa

Just had a terrible customer service at Levi's Mall of Africa, I bought a Jean last nite 07/09 I tried it and it felt like the right size, wen I tried it this morning I realize it was actually too long for me, I went to the store this morning to exchange it to 36/32 instead of 36/34 and I was told that I can't exchange or return because I have already tried it even thou their policy says I can return within 21 days,mind you the Jean is still as I bought it last nite 07/09