Test your system using an external display via the mini-DP connection if the displays image is good you’ve proved the issue is within the internal display system.
Sadly, your issue is a damaged LCD panel, it’s not the cable connection.
The older MacBook Pro Unibody systems used an older communication system between the logic board and the display called LVDS signaling. In the Retina systems Apple needed to jump to a newer standard called iDP (also known as eDP). If you guessed the DP is DisplayPort you’re right! Its a variation of DP signaling.
Why it’s important to understand this is the symptoms between the two systems is different like the differences when we went from Analog to Digital TV signaling over the air. Like how you had to move the rabbit ears to get rid of the signal ghosting unlike digital TV which just doesn’t get into this type of problem. Here the iDP signal won’t create bars like the older LVDS cable would if the cable or the connectors where damaged. All you would get is no display or image blocking.
That fact the area is not moving also supports the conclusion the panel its self is damaged. Here the decoder logic (T-CON) is damaged. You likely had something heavy placed or dropped on the lid which damaged it.
Here’s the needed part MacBook Pro 13" Retina (Late 2012-Early 2013) Display Assembly Right now iFixit is out of stock here’s the Apple P/N you’ll need to find 661-7014, and heres the guide you’ll need to follow to replace it MacBook Pro 13" Retina Display Early 2013 Display Assembly Replacement