@Jessie--Katie-And-Lindsay0
Hope you are well.
As @Susan151 mentions above, if guests contact Airbnb they will most probably side with them as it could be regarded as an exceptional circumstance.
Maybe first try to negotiate with the guest and explain your side- as they did stay the nights they did, so it seems unreasonable to me, that those nights are not valid in their eyes. It’s not as if from the first night they had no water or electricity, which you still provided and your limitations were clearly explained after the incident.
I think guests often do not see how any refund can affect hosts as they have no insight on Airbnb’s business model so maybe educate them on this- as they probably only see this massive cooperation losing out and not the service provider (you). Kindness and education goes a long way especially in such tricky situations.
If they do contact Airbnb later, then you can refer to that exchange and say that this was agreed upon with the guest as mentioned (whenever) and therefore a full refund would not be possible as an agreed refund has already been approved by both parties, stand your ground- though but fair.
If they communicate with Airbnb prior to coming to any agreement, then point out how you’re were very open from the beginning of the incident and solutions were provided, even though they stayed those other night without any associated or mentioned problems (from their end). For me only a partial refund for the unused nights should be acceptable (as an act of goodwill) but honestly it is not my business- best advice I have given is do you and be though but fair.
As a host you did incredibly well to accommodate them based on the solutions you provided!
Good luck to you!
Yadira
ps, if you need to tag anyone @ (Name) otherwise the person prior will probably not see it. X