Ok so I got a massive boxset which is House seasons 1-6. In the fifth season, there should be discs 1,2,3,4,5 and 6. instead there are discs 1,2,3,4,3 and 4. There are two copies of discs 3 and 4 but no copies of 5 and 6. It was bought from HMV and I still have the receipt. Could i take it back and get a new one? Thanks.