one plus serive center Mobile fix 10 Vijayanagar stage Mysuru - Display replcaement

i have requested for new one plus * phone display on *nd August **** at Mobile fix (#**, Vijayanagar, *rd stage Mysuru-******), one plus service center, Mysuru, India. After * month * days, the replaced display found to be defective and verified by the same service center as mentioned above and agreed to replace the display. However, they have said that they don't have stock and said to come back after * weeks. So on September **th **** the display has completely block out/gone bad and i contacted back the mobile fix service center and they have informed come on ** sept ****. When i have visited the mobile fix service center on ** Sept ****, they have said that there is traces of physical damage now so we can not replace the display. i believe the damage would have happened while i was carrying my mobile back to the service center due to the tight jeans. However, the damage was not visible. Also, it was considered as a defective peace by the same service center * weeks before and they did not replace it because of out of stock or any other reason. However, now they are putting whole liability on me saying that its physical damage. i was wondering how one should consider the physical damage on defective items. i have attached duly signed bills along with details of the damage quoted by the service center person. Please look after matter very seriously. i look forward for your response.