Very angry and disappointed

I am very disappointed with the service I keep receiving from them , first I bought something for my son and when it didn't fit he was told they can only reverse the transaction and not exchange it , as I would need to come back to re- buy the correct size and that is their policy when using an account. Even when I complained the regional manager told me that is how they work and there Is nothing they can do, I let that go and never bought the product again. However I still went back and bought a cellphone and I misplaced the receipt I have been to two of their shops and they bought don't even offer to take it for repair as I don't have a receipt as whit cellphones they need the receipt , however I used an account. I thought that if you buy something they are suppose to keep your record for at least 3 year but hey what do I know cause now I have a cellphone that I am paying for that hasn't been working for +-5 months. I understood the first store I went to as they said to me the store that I bought the phone keeps documents and I should beg them to look for the copy for me , which is what I did by still I have the phone and it's not working and no-one is prepared to help. Cause when I went to that store I was told the person only works during the week, so I must take a day off because clearly from my previous experience I am scared to send someone as I never got helped the first time. and it's not like this stores are in the same area, the first store is in Benoni and there other in Daveyton Mayfield square and I guess they are saying since you were able to go there surely you can go back who cares that you are here right now. But surely what I am expecting I am black and going to black surrounding stores and surely all retail stores have shown that when you are black so is your customer service.