I have a similar problem with Heathrow Worldwide DC.
I posted an International Signed For package to Germany from the U.K. on 26 July 2013.
It arrived at HWDC on 27 July at 04:49.
As of today 08 August, it is still there.
What to do ? There is no way of contacting HWDC.
And even if I could, how would they find my package ?
Very frustrating.