Bad service ever

Bad service ever I went and purchase a sneaker for my kid in somerset sportscene I used my credit card and my reward card then my child came back from EC and said she don't like the sneaker so I lost my receipt I advised them I'm willing to get my bank statement and also they can check with my card they said no they won't be able to do that. I understand I should have kept my receipt in a safe place nd I never thought my child won't like the sneaker know I'm stuck with a sneaker that my daughter does not like bad service ever