What a bummer for Kels + Matt, but this happens in this biz. You'd have had no shortage of volunteers for an MMF.
I've had maybe 3 or 4 ladies fail to turn up when staying at a hotel, one bottled it 20 mins before kick off. It's their loss. As the SP deleted emails and failed to have the decency to communicate, that's bang out of order. While you've had a good time, you could have fucked each other's brains out at home and saved £100, and personally, I'd name and shame.