Bought a radio controlled car from waitrose just over a week ago, its broke and i don't have the receipt?

i bought it for my sons 2nd birthday its only a kiddies one and he loves it, but it all of a sudden stopped working properly and just makes a loud screeching noise and the wheels wont turn, but the problem is i didnt keep the receipt and i threw away the packaging, it worked for 3 days then it broke, do you think there is anyway waitrose would change it, i know im stupid for not keeping the receipt,