Washing the Mattress Cover

Yesterday, my husband went to the dry cleaner to receive our mattress cover, but it still has a strong stench. It still smells like bleach and half-dried cloth. Before we asked them to get it dry cleaned three weeks ago, it didn't smell like this at all. He asked the dry cleaner to refund us, but they didn't accept it at all. While we had paid $60 to the dry cleaner, the mattress cover became like a big trash because of strong stench. :(  He brought it back to our home. Today, we tried to wash it in our bath tab. We are afraid that it might shrink, and the terrible smell might not be removed. However, we want to try it before we give it up.