One plus - Defective one plus complaint on display issue

After ** days vertical line start appearing on phone when i connect service center they accept this is manufacturing defect will replace in * days and give job sheet on ** april ** but after many follow up one and half month passed today still neither issue resolved nor i get service denial letter so amazon can refund even still ahmedabad service center not have clarity when display arrived. Here i have made big loss of two month warranty and phone depreciation and reduce of market value apart from it due this issue i have suffer with lot of mantle pressure and despite of purchase such high value phone i am phone less since one n half month and