Broad band

my son(9years old) had a birthday present bought for him off a friend ,when opening the present part of it was missing so took it back to tescos and explain that it was a present so not have receipt i was basically told to go away and ask friends mother for reciept which i said i didnt know the mother and wasnt going to embarass her by asking for it . i was told i could change it so did this only to find the same items missing again, i returned to store explained again and this time told nothing they could do about it .the product was only being sold by tescos so its not like i bought it anywhere else. no joy at shop so emailed customer services twice and im still waiting for a reply, wont be shopping with them again.