Pick 'n Pay Bad Service

I am super angry and disappointed with your services, I went to Pick n Pay Nkomo Village in Atteridgeville, someone bought me a present of nappies in pickn pay and unfortunately I don't have a receipt as it's a gift, I went to exchange as the nappies are small but the manager refused to help me, tell me what am I supposed to do with small nappies as they are a gift