Bad Service from Game Stores and Mobile in Africa

I bought a Xiaomi RedMi 4X at Game Stores. 10 days later the phone stopped touching. I took it back to the shop and they said the phone has to be fixed. How do you fix a new phone? From the 16 of May I have been without a phone because it died. Game Stores doesn't respond on Twitter. Mobile in Africa has been having my phone and i use it for business. Why is it so hard to right your wrongs guys? Just refund me and life goes on. Please