Holding from a buy my position from $142 was just completely forced liquidated at $110, no notice/email/anything whatsoever and the required margin was nowhere near what I had available.
a move down of more than 20%.
Are you sure you really had enough additional margin in your trading account?
And more specifically: did you care not to fund your margin with BTC
in a situation where the market moves down? Since the value loss of the BTC will additionally reduce the value of your margin.
I still had more than enough to cover in the account, I even still have .6 BTC after forced liquidation of entire position. Then it in turn sold my BTC's @ 108.
...another thing to be aware of. When the system detects that your position should be force liquidated, it issues a market order. Due to execution lag this market order will be filled by some price hopefully not too far off. But basically this is just random, and it can be very far off when the market moves quickyl; this is probably the greatest fundamental risk of the business.
That being said -- I'd recommend to look at your order history and check the numbers; if you still think the engine got some calculations wrong, you should contact the Bitfinex support.