lines across ipad screen

Hi

Has anyone encountered a similar issue with their iPad or iPad Pro? It was purchased as an Amazon Renewed product and the problem began around the 90-day mark, which my father-in-law did not mention to me. The seller insists that we have caused damage or water damage to the screen, but Amazon will not intervene. The device is protected by a sturdy case, with all parts including the screen covered, and it is voice-activated due to my father-in-law's MND.

it's a Apple 2021 iPad Pro (12.9-inch, Wi-Fi, 128GB) - Space Grey (5th Generation)

It's been factory reset and even the black startup with apple logo was disfiguring with lines at one point. My fear it's it's been 'renewed' by the seller with an after market screen and not fitted right??

thank you

Any assistance in identifying this fault would be greatly appreciated and aid in my dispute with the seller and Amazon.