I did the same, transferred the following games one after another, not simultaneously:
- Bought plants n zombies on 3ds in the morning (so yea the store worked then)
- bought Airport Mania on dsi
- transferred Boxlife, Picopict, Sujin Taisen, Tales in a Box, Airport Mania, Chronos Twins.
After that, error screen on both shop and transfer screen.
Hope Nintendo mails you back a solution. Be sure to let us know 
