Your SIMPLE IRA contributions are shown with code S in box 12 of your W-2. A correctly prepared W-2 will have this amount excluded from box 1.
Box 2 is tax withholding and has nothing to do with what is shown in box 1. Perhaps you meant box 3 or box 5. I would generally expect the amount in box 5 to equal the amount in box 1 plus the amount with code S in box 12, which , if I interpret what you are saying correctly, agrees with what you see and the W-2 is correct.
