"The kindergarten teacher is not going back into the department store."
Translation:Az óvónő nem megy vissza az áruházba.
That would be correct if it were a declarative sentence, eg: "The kindergarten teacher is going back into the department store." = "Az óvónő visszamegy az áruházba".
However in a negative sentence verbs with certain prefixes "fall apart" the following way: "nem + verb without prefix + prefix".
In certain really special cases there can be exceptions to this rule, but that's not really worth discussing.