This type of a store is a franchise. The "owner" pays Sears for the use of the name, a royality and thus there are covenants built into the agreement to protect the good name of Sears.
Although the owner "owns" the business, Sears owns the name, which is the foundation of the business. Sears has the legal right to yank the franchise and if the Sears name is poorly represented, they will.
Start with documenting the issue, submit it to your boss, and if it is not resolved, keep moving up the chain of command.