My guess is that your magnets are leaking. You should be able to shut everything down and have the fire go out.
Try closing off one thing at a time until you can make your fire go out.
Stuff the lower intake holes full of aluminum foil instead of the magnets.
My lid does not seal on the rim, and I can kill the fire in mine easy.
If you think it's the lid, roll up some foil and put it around the edge of the lid and jam the lid on.
Find your air leaks and you will be in control again.