I travelled half way around the world to see St Peter's Basilica and I chose Get Your Guide to help me do it. I went to the right place at the right time - and waited for over an hour and a half - to collect my ticket. But Get Your Guide weren't there. I was forced to leave without seeing my dream.
I contacted Get Your Guide later that day, but it took them 10 days to respond to me. They intimated that I was lying, but reluctantly agreed to give me a refund.
I would suggest, if you really want to see something, any other tour company would be a better choice.