I got a 72 hour ban last night, as well, for actions yesterday. I was doing all kinds of things against ToS so I couldn't really peg what it was. I was running FATE bot while I was remotely monitoring it from work, though I had it up the entire time on a second monitor. I was using Combat Ex during a few dungeon runs later that night. I think what may have actually done it, and this was stupid to do and is entirely my fault, but I mentioned the remote chat program I was using in my fc. For some reason it didn't cross my mind that this would be against ToS. Just seems like such a harmless thing to do.
Most likely the chat program, I use EX Combat Assist for every job I have yet to master which is like 6 out of 9 jobs everyday and it doesn't look suspicious and if no one calls you out on it then even moreso. If you were monitoring your bot from work and you see that no one has yet to accuse you then most likely no one is suspicious, leaving the only true blunder being telling everyone you're using third party software, even if just for chat.