FIX IT PLEASE

I recently bought a Nokia Lumia 520 from from you.The phone had an issue re:it would switch off automatically and the only way to get the screen active again was to plug the the battery charger in every time-i replaced the battery with a genuine Nokia battery to see if that would sort the problem out.It did not and i sent it in to Game for repairs.Two weeks later i was told the phone was ready and that i had to bring my IMEI number in when i had to collect the phone why the **** i dont know.I received the phone back and it is still doing the same thing.I dont like having my time wasted.I suggest vwhoever repairs your phones to deal with someone else,I phoned Nokia South Africa repair division who are authorised to repair these phones and they told me that my phone was not sent into them.Now i dont know what mickeymouse company you guys use for phone repairs but if i found out that Game is not using authorised Nokia repair centres there is gonna be hell to pay.I want this problem sorted out and expect a timeous answer to my request-the phone still has a year warranty left on it.