Samsung - 3 phones back to back flickering issue

I had purchased s ** mobile phone and it started flickering after *months ,when I went to service center as the product was under warranty still the team denied and asked me to pay ***** for the repair and they are making excuses for althat it is my fault as the paint have come out they are saying phone fell down ..despite of informing them that phone did not fall ,second time when I went to service center again another reason they are saying dat there is impact damage so we will charge u..they are giving different reasons whenever I am visiting to get the phone repaired so I raised a complaint with samsung team and they called me to bargain and were offering me **-**% discount but I denied as I need the phone to be replaced because this is *rd time happening with me , previously in **** same flickering issues happened with me in year **** I had raised complaint with service center with complaint ref#********** and same happend with s** plus in **** I had raised complaint with ref#********** and now with s**in ****,I can barely used phone for *-*months and the issues comes up .I had to face so much loss for *samsung mobiles so I want my phone to be replaced and assured dat the issue will not come up again.Even google says that there is probelm with s** of paint the complete review is there as well.kindly help me as soon as possible