Parcelforce

extorting money from people

I've ordered a parcel from US, it was an electronic device I manage to buy really cheap. I've paid $38 (!!!!) -almost the same amount as price for shipment to keep the track of it and what I got in return??
A letter from BLOODY PARCEL FORCE saying that 'delivering parcel from overseas is a subject to payment of custom charges raised by UK Border Agency on behalf of HM Revenue & Customs'. £28.31. I am asking: for what????????
I've already paid delivery cost, sender hasn't been informed about any additional costs eather..