You are angry that somebody has cheated you. You are in a specific frequency.
The person who has cheated wants to take the money for his own good. His intention was to make money and not to cheat you. It is only an action and not an intention to cheat you. So, his frequency is different from yours.
Therefore, if you keep cursing him, your thoughts don’t affect him as he was thinking in a different frequency from yours. The implication is that those thoughts keep you under the curse forever.
It has to be healed. Otherwise, you will invite such incidents in the future.