If you have received a faulty delivery, you will probably need to reject the goods you have been sent. You can usually do this if the goods are defective or were damaged before clearing customs. You can also reject goods that are not in accordance with your purchase contract. You may not want to pay import VAT or duty, or you might want to reclaim any VAT or duty you have already paid.
You must notify HM Revenue & Customs (HMRC) in advance, and then dispose of the goods. Claims must be made within a year of the duty becoming due. You can do this by exporting them outside the European Union, for example by returning them to your supplier, or destroying them.