Hi Jean,
Welcome to Microsoft Community.
I'm sorry to hear that you're experiencing issues with your Surface Dock 2. If two of the USB ports are not working, it's possible that there may be a hardware issue with the dock. To open a warranty case, you can contact Microsoft Support directly. The support agent will be able to assist you with opening a warranty case and getting your dock repaired or replaced if necessary. Contact Us - Microsoft Support
I hope this helps! Let me know if you have any other questions. Your SincerelyHahn. W - MSFT | Microsoft Community Support Specialist