I mistakenly booked the wrong date for a sightseeing tour of Seville on a recent trip there with my girlfriend, but cancelled it with a week to spare. It was very popular tour, so I knew it would re-sell. On the booking confirmation and the ticket there was no mention that it was non-refundable, but guess what... That's exactly what Booking.com claimed. The tickets combined cost €91 which I'm prepared to let go. What I don't like is being told something that wasn't backed up facts, then being ignored by their customer service team. It's not the first time I've had an issue with Booking.com. On a trip to Italy last year I hired a car through them, only to find out that the hire company had no knowledge of my booking. Despite me showing confirmation to them. I paid again direct and hoped to claim back from Booking.com. Again, they were most unhelpful and I didn't get my money back. There are other booking sites, I'd advise to use them, or book direct.