Training the dog for proper behavior

When our 2 dogs were still puppies we hired a dog trainer to teach the puppies the right behavior. The first command they learned was “sit” which seemed to be easy. It was followed by some other commands. The training was conducted 3 times a week with 1 hour of session for each puppy who were both 4 months old.

After more than 2 months, our dog training was done and the dog trainer said goodbye. Now here comes the problem that our puppies wouldn’t follow our commands. And it came to pass that they are now 8 years old and the only command they know is Sit.