Disputing the review
If the negative review includes: threats of violence, cursing, pornographic content, adverts, spam or comments related to a persons race, ethnicity, religion, gender, disability or sexual orientation, most sites will remove the rating. You will need to flag or report the review, depending on which site it's from. You can hide your Facebook ratings, however, this will include the good ratings too.
The best way to 'hide' a bad review is to bury it with better ones. This, my friends, will be down to you!