Kulula.com timekeeping and bad communication

Flight mn909 Friday 2 March 2018 departure time from O R Tambo 07h50 . We only departed after 12h00. Sunday flight MN 926 departure time booked 13h35 at 18h00 received first sms that the expected departure will be 19h55 . If we depart at 19h55 it means that in one weekend I have waited 11 hours at the airport due to Kulula delays. Kulula do not respect your time . WATCH OUT