Can I sue after I bought a pair of expensive tennis shoes that are defective?

As far as liability is concerned, I'm not sure it is a "shoe in". It would be up to a judge to determine that. If you really want to sue, you will need to go to Small Claims Court. Call District Court and ask for Small Claims Division and they will provide you with all the info you need to do that. However, I would consider the costs of pursuing compared to the potential recovery and your chances of winning. You may be better off simply writing the manufacturer and setting out your complaints. You may find that they are more than willing to do what it takes to make you happy without going to court. Good luck.