They provide an opportunity to understand a perceived failure of a system.
It may be a failure to deliver on those expectations.
The failure may be a failure to communicate expectations clearly.
If you did not communicate effectively to this person, you probably did not communicate effectively to others.
(Or they may be crazy, in which case it is an opportunity to make sure that a reasonable person having done minimal research would also conclude that they were crazy and decide to ignore the feedback)
For further actions, you may consider blocking this person and/or reporting abuse
We're a place where coders share, stay up-to-date and grow their careers.
Negative reviews are incredibly valuable.
They provide an opportunity to understand a perceived failure of a system.
If you did not communicate effectively to this person, you probably did not communicate effectively to others.
(Or they may be crazy, in which case it is an opportunity to make sure that a reasonable person having done minimal research would also conclude that they were crazy and decide to ignore the feedback)