Parcel held by Post office custom since 20/09/2017

My parcel, from China, has been held by post office customs since 20/09/2017. I have tried to get hold of them via email but it takes them weeks to reply, and i tried telephonic method of communication but there is no answer still, the phone just rings. It has been nearly 1 month.

Tracking No: RE ********** 19SE