I had a similar problem two days ago. On the two occasions I called up agents on the centralised Malaysia number they were useless, but the London agent did for me straight away, although be aware that if you try the number published on Google (+44 207 341 2000), that number has a recorded message for punters to call a +44 871 423 9090 number, but when you call that number there's yet another new number +44 330 365 0080.