Samsung grand neo plus earpiece damaged

I have a samsung grand neo plus for about 4 months now or at least its been at vodacom repairs most of the time for a faulty earpiece. Its been exchanged by samsung and the new phone still has the same problem and has already been in 4 times at 2 different vodacom centres in 3 months and when it comes back it has the same problem within a few days. They dont want to guve my money back and they dont want to exchange the phone for something entirely different and im fed up with if. Their tecs just say everyting is fine. I have even phone jhb headoffice and they just tell me nothing is wrong. I know of 9 other grand neo plus phones with the same problem.