A few thoughts.
Over the past two weeks, BW has been issuing "virtual goods sales" bans to both botters and credit sellers - which means it's possible that it was actually your space bot accounts which were caught, and then linked to your other accounts, regardless of what the email stated.
Per account linking, if BW really is that good at tracking every conceivable way to trade goods or credits (GTN, guild bank, direct trade, third party, etc.), it might just be more cost effective to sell from the bot account directly and be ready to start over once caught. However, if you do find a relatively good way to trade under the radar, I would love to hear about it.
Good luck!