I booked four services with Viator for my recent trip to Paris. First was car service to meet my wife and I at Orly airport. Our plane arrived 45 minutes early and I called them and was told that they could not get a car to pick us up early, which I understood, however, the car that eventually came was 30 minutes late.
Second service was skip the line tour of the Eiffel Tower. The day prior to the tour, I received an e-mail that they had stopped offering skip the line tours since July 1st and they waited until the 3rd week in August to notify me. I cancelled the tour and am still waiting for a credit 5 weeks later.
The third and fourth services were skip the line tickets for the Louvre and the D'orsay museums. It was unclear that we had to pick up these tickets personally and that our vouchers were not tickets and we had to go to the location twice because they would only give us tickets for that day and not a day ahead. I will never use them again.