Guest score bad point after cancelation?!

Hi all,

I just had a bad score from my canceled guest. Don't know if anyone had this sad experience or it's just me.

This guest request a free cancelation just right after he booked with the reason " Found a better place".

I approved his free cancelation ( as I usually do with other guest), but yesterday he scored a bad point on my place (total 6.0), we usualy got good point from our guests (around 9). That's an disappointment and angry for me because it's total not true, he didn't even spend a night at my place and he can do that horrible things to my place, which cause a big misunderstanding for our future guest.

Can anyone please help me with this situation?

Many thanks