I have used fusible batting from Joanns and never had a problem. that is terrible, but it isn't your fault. I would call the people you bought it from and if they can't help call the mfgr. and if they blow you off tell them you are demonstrating use of product for a big quilt show or some other drum-beating nonsense and get attention from a tech rep of the company. That is a clear case of material failure to perform as advertised.
My only thought about a DIY approach is to use mineral spirits or paint thinner or nail polish remover. I suggest you iron the stuff on some scrap fabrics and then try different approaches.