@Lindsey260 AC has been completely unnecessary this week... Why in the world did they wait until after the close of business hours to let you know that there was a problem?!?!? If they'd told you Monday night or Tuesday morning, you might have more options for fixing.
On the one hand, it's out; on the other hand, it's been unnecessary... You offered that they could leave and they elected to stay. So, perhaps ask them if they feel they need some compensation for the worry? Maybe they'd be content to receive some consideration on a future stay? Or maybe they're reasonable people who realize that things happen with houses and they aren't at a hotel? Unfortunately, people are variable and ABB CS are unreliable, so really this could go any number of ways.