Sorry to hear about your Opodo problems. I hope you still make it to Vienna at a reasonable time - and don't let it spoil your enjoyment of the city and your company.
It did make me skip a heartbeat though - we booked through opodo as well to go to Sofia on Monday. They did send us a schedule change notification a while back - but that was only a 5 minute change on the departure time. And I've just checked the booking on checkmytrip - all seems to be ok.
I did notice though that the schedule change notification came from an unusual domain - not opodo.whatever but mailnj.custhelp.com. Could something have been caught in a spam filter?