I would like to open a flag against this guy, As he tried to destroy my reputation and wasted my time
That is not the right reason to create a flag against someone. I mean if you check the type of supported flags,
Due to various concrete red flags, I believe that anyone dealing with this user has a high risk of losing money. (This flag will only be shown to guests/newbies.)
This user violated a casual or implied agreement with me, resulting in damages.
This user violated a written contract with me, resulting in damages.
your case doesn't fit any of the above-mentioned reasons.
He tried to damage my reputation, So I can say in that way it comes under the 2nd category.