Does iFOREX use Margin Call?

We do not use Margin Calls.
The Term Margin Call is wide spread among Forex brokers and it refers to a closure of all open positions by the broker when the level of minimum margin security is breached. The customary minimum level of margin ranges between 1% to 2% during week days, increasing to 3% to 4% over weekends and holidays. As a result, positions may be closed despite a positive free balance in the client account.
iFOREX philosophy is to allow investors to make a full use of their free balance as margin for their opened positions, which means that positions will remain opened as long as the investor has a positive free balance in his account.