Question about gap up opening stock

i placed the following order (after market order):
stock name : atlas cycles
quantity: 200 shares
the stock was closed yesterday (6 jun 2017) at 328.
i placed the buy limit order for next day (i.e. 7 jun 2017) at night of 6 june 2017.
my buy limit price was 329.
the next day (i.e. 7 jun 2017) , the stock opened with gap up of 345 price .
when i looked in the morning after the market opened, the order was not fulfilled although the stock was trading at 345, (higher than my limit price of 329) , why this happened.
my question is:
the stock is trading at 345, even then my limit order of 329 rs was not fulfilled , why so?
what care has to be taken while placing after market order?
are there any limitations by zerodha for placing after market order like minimum order amount should be rs 25k or any such thing like that (i am not sure about this, please clarify)

@smartinvestor

When you place a BUY LIMIT ORDER @329 the order gets filled only at 329

A seller should come forward to sell you at 329.

When the Stock opens gapup at 345, no seller will be willing to sell you cheap at 329 when the current market price is 345

Thus, you buy order remains unfilled .