In reality, this is a spiritual issue -- because God is concerned about everything that concerns us. If you have children, you know you're concerned about everything that might harm them -- and in a far greater way, God is concerned about everything that might harm us.
God also knows -- far more than you do, frankly -- just how destructive your addiction to shopping could become. Not only does it hurt you financially, but it has made you a slave of something you can't seem to control -- and that is wrong. God doesn't want us to destroy ourselves, and anything that threatens to do this is a sin. Jesus warned, "Everyone who sins is a slave to sin" (John 8:34).
Have you ever asked yourself why you get such pleasure out of spending money for things you don't really need? I don't know the answer; it may even take the wisdom of a gifted counselor to help you understand your deeper motivations. But don't back away from seeking an answer; it may be the first step toward solving your problem.
But the most important step you can take is to commit this problem -- and your whole life -- to Jesus Christ. He loves you, and He wants to help you deal with this issue. Open your heart and life to Him, and let Him set your feet on a new path -- a path of responsibility and freedom and new life.