Unacceptable service

I have paida premium to fly BA over the festive season. On the 19th December I reciived an email from BA: my flight on the 21st December BA056 'is delayed'. Instead of departing at 20.20, it will now depart at 23.55. Being a weekend, I had to wait for the day of my flight to make inquiries. Which were futile, as nobody could tell me the problem. Meanwhile, time of departure gets ever later. Now basically 1am. I could have paid far less and flown non-direct to London, with the same or better result. I did not want to arrive mid-morning, and I do not want to spend most of the night at the airport. For what I'be paid, this is just not good enough. I have now found out it was something to do with the plane needing repairs in Singapore.would have been nice to know the facts sooner. But still not material to my complaint - BA not delivering the service I've paid for.