He's taking advantage of you and running through your aids. You'll need to ride him and not just be a passenger. Ditch the jumps until he understands stop. Ride him at all gaits and throw in halts or downward transitions every 10 strides or so. Make sure you get a response when asking for a downshift. Use as much force as necessary, but as little force as possible. At first, when he offers even a hint of compliance, reward him. After you know that he knows what you're asking for, make sure you get total compliance every time you ask.
Once you've got it working on the flat, move up to ground poles and do the downward transitions after the poles. Only then should you move back up to jumps. He should be able to stop on a dime only strides after a jump, not rushing off at his own speed. good luck.