First you'll have to figure out if it's a ban on the NNID or the console.
For the former the solution is obvious: change NNID (by deleting the act driver's save)!
For console bans (which usually also come with a NNID ban, in the case of memeverse) there are further sub-types: on the serial number (edit it - I've assumed you have A9LH and CFW for this entire message), on the MAC address (replace wifi card), on the device ID (replace SecureInfo and LocalFriendCodeSeed with ones from a clean console), etc