Pathetic experience dealing with cellphone return

I recently took my phone for repairs to a different store. Since I needed the phone as in like yesterday opened an account with Edgars Promenade mall. Bought a brand new ZTE Blade S7 on the account. Just a day later I picked up that it's battery quality gets drained abruptly such that I had to charge it 3 times to last through the day when it has been used for small casual WhatsApp chats. Took it back to the store and they rubbed it off me saying I had background apps running, I gave them the benefit of the doubt and went home keeping everything closed and display settings to minimum, made no difference. Went back to the store they still tried to look for excuses, so basically they were buying time so to get over their 7 days but I decided to leave it there, that was on the 8/09/17 bought on 05/09/17. I was open to take different make under the same price range but they blatantly refused and took it in for inspection so I had to wait 21 days. ****ed off by that reached out to store manager who was by all means of the word"useless" in its very sense. I called customer service with the help of a very helpful guy from Edgars Salman center and spoke to Suvana in Head office. I can not count how many times she started every sentence with the word"unfortunately" and she referred me back to the store. After 2 weeks the phone has been approved as Obf (out of box failure) it is only now that they are willing to replace it. After all the experience I had I have no interest whatsoever to deal with them. They refused to credit back the account or refund, only option given is the replacement of another handset. Even though I no longer need it as my old phone had been returned from repairs, could use the credit for something else but no they refused, I can only take a phone with it. I paid their account and closed it sametime as I am sick and tired of all their dealings.