These lines typically are resultant from the something happening to the LCD cable when performing the installation. These flex cables are full of electrical connections and if they have any serious bends, creases, kinks or tears in them, those electrical connections may have been severed. They are flex cables and are meant to be able to curve but when we say "serious bends, creases, kinks or tears," we mean the sort of crease that you would make when making a paper air plane. A serious crease such as this will damage the flex cables and not allow the corresponding piece of the screen assembly to function properly.
If you do not see any damage of this sort, please photograph the flex cables stemming off of that screen assembly and send those photos to firstname.lastname@example.org with your name, order number and a brief description of what you are experiencing. Once received, our warranties team will evaluate the condition of the screen and determine if the customer is eligible for a replacement or not.
If you are not eligible for a replacement, we do have a 25% off coupon code in place to make the purchase of a new screen less of a financial burden for our customers. We also highly recommend speaking with a certified iTech in your area as they have screens on hand and take liability of doing the repair correctly off of the customer.