Have you tried cleaning out the USB C port on your phone? What I do is take a small toothpick and completely flatten one edge with a rolling pin and trim it down a little bit so I can get into the port and dig out all of the dust and other debris that's in there. That typically does not allow the plug to go in all the way into the port which makes it seem like it's loose. Hope this works for you.
Hello, Welcome to the Community. We can certainly understand the disappointment of a loose charging port. If you have already tried different cables, and they are all loose like how you are describing we would have a certified technician take a look at the device.
You can use the following link to find a list of service centers in the U.S. that can do the repair: http://www.samsung.com/us/support/service/location or by calling customer support at 1-800-726-7864.
