Hi, welcome to the forum!
Unfortunately, this is a common problem due to the lack of strain relief on the USB cable. (For future reference, it is a good idea to use a tie wrap to anchor the USB cable to the printer frame to protect against this kind of damage.)
Did the connector break, or did the traces lift from the PC board?
If it is a broken USB connector, you may be able to get one from your local electronics supply shop, or online from DigiKey or Mouser.
If the traces lifted off the circuit board, you may have to do some careful repair. I use light gauge “teflon coated wire-wrap wire” for this kind of repair. Follow the traces back, use a razor blade to scrape away the protective coating, and restore the broken electrical connections.
You can also replace the controller board. Velleman sells the replacement controller board, or you can use the controller for the K8400, or you can use an Arduino Mega 256 and a RAMPS I/O shield.
If you post more details about your situation, I can help you find more information.