Phone not getting repaired (I am being **** to)

Good Day<br> <br> I have booked my wife's phone in for repairs at the branch in Centurion mall as the phone freezes and drops calls and over heats<br> <br> They booked it in and returned it to me and said nothing is wrong<br> <br> After a week I had to book it again as it still done the same thing and I was told again that nothing is wrong<br> <br> It is now the third time within two months that I had to book it in for the same reason<br> <br> Please repair my phone as it is a lie if I am told nothing is wrong but the phone still does the same thing<br> <br> 3 times is poor service and time consuming when it could have been repaired the first time