I wouldn't give up.just yet. If you can, try on a different computer, even just to see if it sees it. Others have solved similar issues with some of the following:
Trying with several cables, preferably not ones that came with a 3rd party charger, or are just cheap cables.
Unplug ALL usb peripherals that you can, then try all ports on computer.
Uninstall kies, uninstall drivers, install different version of drivers, plug in and if seen in device manager, right click and update driver, manually choose location and browse to program files where they installed.
Install universal adb drivers (links in Sig btw), and try again.
Try when booted in recovery and download mode.
You said before the port was messed up. How is it messed up? You can charge it right?
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