Travel One way ticket to japan

Hi all,
Really hope to hear from someone who has an answer to this question before the 9th Jan 2014:

I am a Singaporean and have at the moment a one-year Cultural Activity visa, my flight will take off a week from now to Narita Airport and the airline is flyscoot. As it is not yet decided of my departure date, only a one-way ticket is booked. Will I get into trouble with the airline or the immigration customs? As I have heard too often of being denied of entry.

Hopefully someone with the same experience can share about this. Thank you

I don't know the answer to your question, but I recommend you contact the place where you got your visa.
Is it the Consulate? Embassy of Japan in Singapore