Complete scam — avoid!
I have just reported OMGhotels to the BBC's Watchdog after having been unable to contact anyone at OMGhotels for the last three days. The only way to contact them is through the email shown on their website, but it must be offline because all I'm getting are delivery failure notifications.
My experience is similar to others: our event was "cancelled" the morning of the event, and had a choice to either keep the hotel booking in London or reschedule entirely with some added "goodwill benefits" to make up for the cancellation. After opting to reschedule at a later date, I've since attempted to reschedule without success. There's nobody to speak to.
The event was a gift from my family, now I have to tell them they've been scammed. Absolute disgrace.