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it is actually harder than you would think to remove a bad review. Google tends to want to leave them there because every business would want to remove any negative reviews justified or not and if they remove the easily than the whole review process is meaningless.
However if it is a case of slander which would be illegal than they do have a legal review process where you could make that claim and they will remove the post if they feel it is illegal.
otherwise what is recommended is to respond to the reviewer politely and point out where he is wrong and mostly to actively ask customers to write good reviews that will drown out the bad one.
or there are professional services run by lawyers that can work with google and the court system to get it removed.