Cayuga Dacha...Lakefront retreat in the beautiful Finger Lakes

Three days before her arrival, I messaged our guest via the Homeaway platform with a welcome email that I send to all of our guests that includes information about getting to the home and about accessing it via our smart lock, and making myself available to answer any further questions. In the message, I told her I would send an invite to her phone number to download the August app so that she could use it to unlock the door, which I did. She responded to my message "Thank you, looking forward to it" and then I didn't hear anything else from her in the days leading up to her stay, so I assumed she had experienced no issues with my instructions and was all set to go. In the past, when a guest has had trouble downloading the app or did not receive the invite, they have messaged me ahead of time to let me know and then I can provide them with other arrangements, such as an actual physical key to unlock the door, or a pin code to type into the lock key pad, since I understand that technology is not always perfect and that is why we have alternate methods. The problem in this case was that Suzanne neglected to tell me she had not received the invite to download the app until 1 hour before she was checking in! Since both my husband and I were at work, we did not realize or see her message until about 3 hours later, when we immediately contacted her with a code. The worst part though is that she was exceptionally rude to my husband when he called her! She repeatedly called us liars and claimed that I had never sent her a welcome email (which she had even responded to!). He said it was the most unpleasant conversation he has ever had and he was completely taken aback at how incredibly rude she was. By no means did it seem like she would have just "let it go." Despite this, we did feel terrible that she was not able to access the home for 3 hours and we appreciate how valuable vacation time is, so we asked her if there was anything we could do to make it up to her (such as give her a partial refund or extend her check out time) but she rejected this olive branch and said her recompense was going to be leaving us a bad review. From a complete lack of communication in the beginning to completely unproductive and insulting communication at the end, this was a very bad experience.