Venice: Doge's Palace & St. Mark's Basilica Guided Tour

I was given the tickets along with the rest of our group on the morning of, they turned out to be for entry on the following day. After all waiting in line, we scanned our tickets and realised this. We went back to the spot where we met the guide to retrieve the correct tickets and they were not there. After multiple messages to the company we were told that we could use the tickets we had for the following day but that was our only option. Many of us were unable to attend the following day so missed out altogether. I have been attempting ever since to get a refund for this as I was unable to see the Basilica which was a huge disappointment, and have been unsuccessful in getting any sort of refund. Horrible communication and organisation. Would not recommend using this company.