The tour should have lasted 3 hours in total, but it was delayed for 40 minutes. When you arrive to Vesuvio, there is not enough time to go up there and come back as they didn't want to stay 40...
The tour should have lasted 3 hours in total, but it was delayed for 40 minutes. When you arrive to Vesuvio, there is not enough time to go up there and come back as they didn't want to stay 40 minutes longer (even though it was their mistake that the tour was delayed). Before booking, check if there is an option for canceling or getting a refund.