All the ways of contacting airbnb are listing in the CONTACT AIRBNB post at the top of the forum you are listing in @Jonathan947 . There are different numbers depending which country you are from.
Why do you want to change the guest review?
You can actually edit your review of a guests within 48 hours of posting it, as long as the guest didn't also post their review.
Well a few reasons, the guest left so e clothes here and i offered to post them bavk, even to his local post office for privacy, there was mess left which i did not worry about i tially at all but afterwards there ate some things missing , he has never repied my communication,and it was nothing about missing items