@Jennifer94 it´s tough. Was there much truth in what both guests reviewed you on? I can only assume that you do not live near the property and you have no way to measure how good the professional cleaning service is. I do not know how many times we have had this problem, but because we live in the same neighbourhood we are able to pre-inspect the property before guests arrive.
I guess you also have to be very careful how you respond to these negative reviews online. If you are seen as accepting and understanding, with a promise to fully resolve these matters, then it shows compassion. But if you challenge it, potential new customers would find it hard who to believe.
My suggestion is to respond to the current review in a compassionate manner letting the past guest know you have taken their feedback on board and you will personally attend to any matters. Re-assuring any new customers that you have attempted to be as accomodating as possible.
How do you do check-ins? Do you have them collect keys from somewhere. I really suggest a check-in person that IS NOT THE CLEANER. This person needs to have a good eye for presentation and any seen problems. This person can quickly attend to matters if need be so that every new guest is presented with a lovely property. Even having this person meet them at check-out will make a whole lot of differene to making your property run smoothly.
The property looks great on the photos and i am sure you can recover quickly. Before you know it these reviews will be pages away from the front of the listing.
I hope this has been of some comfort and help for the future.