Well I would say that he isn't heeling. Stop allowing him to land there when you say heel that will help to start. Are you following a program or just getting started? I havent ever used one but I hear great things about the Delmar Smith Wonder lead. I think he even has a video out.
In 30 years of teaching dogs and their owners how to Heel, I have mostly used a slip collar, nylon or traditional metal choke collar. Used properly it works well on most every breed. Now recently on some BIG & Strong almost adult dogs I have used the Herm Springer Prong collar. Some times you need to think outside the gun dog training box and refer to pet dog obedience trainers for some help.
The quickest way I know to break a dog from pulling ahead or getting in front of me is the moment the dogs shoulder is past my left knee I make an abrupt 180 degree about turn to the right. Put slack in the lead before you turn and give a serious jerk of the lead as you are turning and walk quickly the other direction. The moment the dog get slightly a head do the about turn again. Never had a dog take more than a 30 minute walk to learn how to Heel and remember it for next time too.
The trick is the technique of pivoting on the ball of your left foot as you turn right and taking off in the opposite direction.
I am sure their are YOUTUBE videos of obedience trainers expecially those that compete to show you how this is done.
When you say he is heeling on your foot do you mean walking or sitting?
Heel is the command to move with you at your side. So the dog isn't SITTING where you tell him.
In the sequence "Here, Heel ,Sit" you call the dog "here" , as he approaches lower your left hand get control of his lead and take a step forward "heel" once he moves with you "sit"
He is by your side. After doing this enough it will become his natural inclination.A little stick can help too.
You can't fix what you haven't taught. Teach the dog where heel position is, then teach the dog to walk with you in heel position. Don't leave the dog guessing about why he's being corrected; he doesn't know what he's doing wrong if you haven't taught him how to do it right.