Heel shots are caused because you either move the center of your plane out towards the ball during your swing or you start too close to the ball at address
With a buried lie you must use your sand wedge as a digger to get below the bottom of the ball so square the clubface to dig into the sand and create a more downward swing arc
Reverse pivot means that your pivot is going in the reverse direction that you want it to, when you turn back to the right your weight should follow you and the same applies to the through swing, this is usally the result of a poorly balanced set up