@Cosmin3 It seems that the automated system mistakenly sent your guest a review prompt. If the guest does not stay at the listing, then there can be no review by you or the guest. Perhaps he did not cancel and Air BNB system thought he stayed. Contact Air BNB to have the review removed. Sounds like you have proof on the system that the guest did not stay. If you need help with how to contact Air BNB, see the community guide on this site.