Hello James,
Thanks for reaching out to the Microsoft Community! I’m really sorry to hear you’re having trouble with your Surface. Let’s see what we can do to sort this out. Since you have some troubleshooting done. May i asked if your Surface GO SD card slot beeps when inserting/removing the card? if still not try to go to Device Manager > Disk Drives then If the SD card appears, right-click and Uninstall, then restart your device.
and also did you try to use different SD card? Some cards may not be compatible or may have formatting issues.
incase it is still the same and have an issue, You can visit Harvey Norman or other ASPs listed by Microsoft. They use certified parts and verify warranty status using your serial number.
Feel free to reply for better understanding.
Warm regards,
JayMark