FS PilotShop Not paying sales owed!

I am a manaufacturer with FS Pilot Shop.  I create sounds (software) that I upload to their site to sell.  The files are displayed on the site and can be downloaded (purchased) for the price I set.  I started selling my products on FS PilotShop in December 2013.  I was made aware of their payment policy and accepted the terms.  However, I have yet to be paid for sales in December.  I was advised that payments for December would be sent Between Jan 30 and Feb 1st.  30 days from the past month.  I didn't receive payment within that time frame so I contacted them and I was advised that they would check into it and get back to me.  It has been nearly 2 weeks and no word!  I was depending on the funds as I have bills to pay.  I am self-employed and have little income to get by on.  I feel as If I'm being ripped off and mislead.  It's poor business practice on their part.  If they can't pay on time or at all, then they shouldn't take on new clients trying to sell products.  They advised me against the payment method I chose to receive funds from the sales I make, but it's one that they offered and the best and only option I have.  AND I made over the amount that they said I needed to reach before payment could be sent out.  I don't know what the problem or hold up is but I would like an answer, and the funds ASAP.