I'm sorry to hear this happened to you. Possible causes of lines on the screen are 1. physical damage on the screen, 2. screen cable/adapter issue and 3. motherboard issue.
In case 1, this is the most common cause and problem of RC512 and it mostly can be fixed by replacing the damaged screen with new one. We have the screen replacement guide here. Also here is a video guide. Replacement screen could be purchaced online for about $40. →Link.
In case 2, this could be fixed just by reconnecting the adapter. Please refer to our guide page to open the screen.
In case 3, this is not a common cause but it could be replaced. However, it is not recommended.
Please refer to the troubleshooting page as well. Hope this helped.