This has happened to me. In my case rocking would not help, the pressure plat was stuck to the flywheel, the clutch moved in and out, but no release. I was lucky, I guess, the truck was parked in the garage and I could move the gears in and out as long as the engine was not running. I use the battery, (in first gear) to move the truck forward about a foot. Turn the truck off, switch to reverse, start the truck, with the clutch pedal pushed in, and let'r run into the back wall. The force of the collision will unstick the pressure plate, and your clutch is already in and free. I thought for a while before I did this, I could foresee my drive train laying on the floor twisted with the plate still stuck. Its worked twice for me with no damage to my truck or the drive train. If that doesn't work, well, you got bad advice.
