Hello Michael Elem, welcome to Microsoft Q&A forum.
Unfortunately, the BitLocker recovery key can only be found in the Microsoft account that originally enabled encryption on your Surface RT. If you've checked all Microsoft accounts you may have used with that device and the key isn't at https://account.microsoft.com/devices, Microsoft cannot recover or regenerate lost BitLocker key.
If you still want to unlock the device and use it, it's still possible without the key. You can reset it, but this will permanently erase all data on the device:
- Download the Surface RT recovery image from the Surface Recovery Image download page
- Create a bootable USB drive (16GB or larger, FAT32 format) with the recovery image
- Shut down your Surface RT, insert the USB, then hold Volume Down and press Power to boot from USB
- When prompted for the BitLocker recovery key, select "Skip this drive"
- Follow the prompts to factory reset
Let me know if you need any help. Warm regards,
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