Booking mix up!

I was expecting 2 ladies to check in on friday around 4pm. They were late..... 24 hrs to be precise! they turned up at 4 pm on Saturday!!
Unfortunately, i had already managed to sell one of their rooms (they needed 2 singles) at 9 pm Friday night, after having spent 2 hrs at the pub complaining about my absent guests!!
What are the chances of this happening?.... very slim. I don't think i've ever been able to re-let a room out so quickly.
I managed to find the 'late' guests alternative accommodation, which was quite lucky, otherwise they were going to have to sleep in our loft!!
They were very good about the whole situation and in the end admitted blame. They did say in their email 9th and 10th but what they meant was the saturday and sunday which was the 10th and 11th.
They said they would tell everybody about us and i gave them a leaflet to leave at Tarn House, Stirton, where i'd sent them!
So, all in all a poor w/e in monetary terms!!
My single lady who is currently staying with us, has extended her stay by 1 night.... every little helps!!