I had the same problem. I've tried the freezer, baking soda, antibacterial spray, etc. Nothing works. Nowadays I simply put my shoes in the washing machine with my other clothes. People will tell you not to do this because it will ruin the shoes but I've done it many times for months and my sport shoes are still fine despite being worn 4-5 times a week. Just make sure it's on cold water setting and air dry them with a fan.