I've had similar experiences to this and the messers usually don't respond, they certainly don't apologise. She did have a foreign accent though, sounded Geordie or Scouse or summat, you lot all sound the same to me
Obviously if I didn't have the set up that I do the situation would likely be very different, maybe she wasn't expecting the kind of response that she got, maybe it was a genuine mistake.
I'm perfectly willing to give her the benefit of the doubt. Sometimes life can get on top of you. I'm not going to get my knickers in a twist about it either way.
My bet is that I'll never hear another peep from her. She set up a direct debit last night and we've quoted her next door neighbour who we'll be cleaning in January.