If you took a emergency contraceptive after having unprotected sex during fertile where pregnancy change is high . Will it work ?

It's not 100% effective. No form of birth control is.

How long after sex did you take the emergency contraceptive? What brand did you use?

If used correctly, emergency contraception is highly effective. However, as Alty pointed out, no form of birth control is 100% effective so pregnancy will be a possibility if you have sex.

Why risk pregnancy and then concern over morning after pills? Practice safer sex.

If you were actually on the fertile period. Of course online or phone charts are not always correct. But if you were, pregnancy has a high chance. The sooner you take the pill after sex. 12 hours is better than 40 hours. But it is not 100 percent so, there is of course a chance of pregnnacy.