No-pull harness The no-pull harness is worn on the body of the animal. The no-pull harness differs significantly from the standard harness since it makes it harder for the dog to pull because it distributes energy over the dog's back and shoulders. Like the head collar, the no-pull harness does not teach the dog not to pull, it only makes it harder for the dog to pull.
It's not so much the dog doesn't listen, more that he doesn't understand what you want him to do. Go back to basics and don't punish him when he toilets indoors. Double your vigilance and take every opportunity to put him outside to toilet. The crucial thing is to be present when he does toilet in the correct place, so that you can reward him. This makes him keener to repeat the performance to get another treat. Conversely, if you have been telling him off for indoor accidents he may already feel inhibited about going to the toilet in your presence, including when he goes outdoors. This is one reason why it's important not to punish for inappropriate toileting.
While your puppy is confined to the bathroom or his pen, he is developing a habit of eliminating on paper because no matter where he goes, it will be on paper. As time goes on, he will start to show a preferred place to do his business. When this place is well established and the rest of the papers remain clean all day, then gradually reduce the area that is papered. Start removing the paper that is furthest away from his chosen location. Eventually you will only need to leave a few sheets down in that place only. If he ever misses the paper, then you've reduced the area too soon. Go back to papering a larger area.
A training class is not there to train your dog. Its purpose is to teach you to train your dog so you will need to be committed to train your dog for short sessions (5 minutes) several times a day rather than just simply turn up for classes! This little bit of training everyday will be repaid with a lifetime of living with a well behaved dog. You will also learn to avoid problems before they begin as well as receive help to overcome any that you already have with your dog.