Package at customs (priority mail) for 19 days

My son (12 yrs) bought bike parts from England and paid a priority mail fee. The package landed at Customs Expedited Mail Centre on 9 January 2015. It is still with customs and today is already 28 January 2015. I tried to phone the customer centre, but they either don't answer, or I hold for 30 minutes , or the line is cut off. I have reached a lady who said (on 22 January) it will only take a few more days. But there is nothing expedited about the EMS. I paid a priority mail fee, but now we are waiting and the parcel is not moving there is no feedback. I am very frustrated, because my boy is building a bike and the package has the last parts that he needs to complete the bike. So now we are stuck.