Another couple of data points. I have managed to get through after hold times of 30+ minutes. Calls have dropped both times and SQ have called back efficiently. However nothing else has been efficient, my flight change has not been resolved, and neither agents give me any confidence that they know what they are doing - the reasons (excuses?) keep changing. I have a "case number" and am assured I will be called back...we shall see. This is for a change of a single flight, same class, same route, which should be able to be done online. Very frustrating.