I've heard of this happening to those who get paid by RMTers with RMT'd isk.
One character I still have in my adress-book is a doomheim casualty after getting a wallet turned into a - 3 billion or something along those lines.
Was a CEO in a corp and supposedly the ISK was from the new toon of an old player who wanted to 'help the corp out' from his older toon's wallet.
Ofc, it was actually RMT'ed ISK and there was no mercy from CCP. However, the CEO toon that got fucked did not get banned (the original offender did) but with a -3 bill or worse wallet the toon may as well not exist. A day later it didn't and the corp in question died ofc.
If the pattern is consistent this should not involve RMT'ing suspicions or anything at all because if it clearly shows that you RMT'ed you would be banned (and I am assuming here you are innocent of such a charge
) or had a negative wallet.
I am out of ideas for what it COULD be though, those petition answers from CCP should be interesting.