[...] Afaik, HitBTC has a predatory scheme of charging a monthly fee if you've been inactive for 6 months.
18.4. Inactive Account Fee. In case during 6 (six) months the User has not made a single Trade, or single Deposit, or single Withdrawal of Funds, the Account of such User shall be considered Inactive Account (“Inactive Account “). For all Inactive Accounts, HITBTC applies a monthly fee, which is the equivalent of 20 (twenty) USDT at the current SPOT rate of the USDT to the Currency in which the fee will be debited (“Inactive Account Fee “).
Do this rule has been around since years ago? That could explain why my balance hit zero.
At one point in the past, I got a warning email from hitbtc that someone tried to access my account. Driven by curiosity rather than wanting to secure my account, I logged in and saw that my balance is zero --or if not zero, then it was negligible to be withdrawn-- I might be wrong [and this time, the chance is quite big that my memory served me wrong] but I think I used to had some balance there, not sure which currency was it, but I pretty much sure I left something there. At that time, I thought I must have moved the remaining balance and forgot about it. With this added info, though, I became quite sure I did left something there and got deducted by "inactive account fee". Ahh, well, what's done is done.