Hi. Thank you for your feedback. I hope our clarifications will help you understand better.
1: The reason why the driver was late
The tour actually starts from Reykjavik but you booked it with Selfoss pickup location, as it was last minute booking so we decided to go ahead with it and not waste your day.
2. You got late for dinner reservation
After completing the tour, the driver was curious to take you back on time for dinner reservation but due to over speeding, you got 30 minutes more late and it costed us huge fine as well.
3. $1100 is price for a group of 5 to 8 persons.