When you're at your wit's end is the best possible time to try something else, because you'll be able to see quickly whether it works. Sounds like your little guy is in full resistance mode, which I'm guessing will only be intensified by yet another layer of discipline, deprivation, correction, punishment, threat, or yelling.
ALL behavior, in adult or child, is an attempt to get some need met. You don't have to reflect very long to find this is true for yourself, and it's just as true for your son. If he's not listening, not responsive to your requirements, and not corrected by punishment, something is seriously wrong in his little life. This is not simply testing limits, it sounds like a desperate ploy to find some set of limits that fits his needs better.
I understand that you can't possibly draw a whole picture for us in your request, but is it possible that your expectations are rather beyond what is realistic for a young child? Is your family life possibly over-scheduled? If "everything is a battle," and he's being required to follow instructions OR is dealing with/recovering from another round of correction or yelling more or less constantly, where are his down time and positive affirmation coming from? ALL little kids need lots of time for themselves, to play, to relax, to internalize all they are learning. I see this in my grandson (approaching 5), and in every young child I've ever worked with.
Unfortunately, little kids have very little life experience, so they do what they know. That often looks like stubbornness and resistance to their parents. And it's often a childish imitation of the behavior and tone of voice they hear from their parents. So if you speak to him in an abrupt or impolite way, he picks that up and amplifies it as "smart talk." If you see your existence with him as a battle, that's how he'll see his existence with you. He's not in a position to change that, but you are.
I hope you'll do some reading on Emotion Coaching (you can google this for the basics) and try an approach that gives him a chance to identify his needs and help find ways to solve his own problems. This can mean more cooperative behavior, and a pretty quick turnaround. But it requires attention, empathy, and respect from the parents.
There's a most wonderful little book I use with my grandson and other young people, called How to Talk So Kids Will Listen, and Listen So Kids Will Talk, by Faber and Mazlish. Some parents with some pretty disturbed and worrisome behavior in one or more children have had almost miraculous results using these easy-to-understand and sensible techniques. I hope you'll give it a try; it just may save your sanity.
