Your deposit isn't considered valid by the system because it's under the minimum amount so your funds will be sent back automatically to the address you used to deposit.
It's great that foolazz22 raised this question, I know it's not the mixer's fault but what happens when fees are pretty high, in other words, in order to refund him his $15 at least $10 of it will go in fees, on the other hand, setting low fees might make the transaction stuck for a very long period of time.
What I propose instead, if possible, is to give the user enough time to add a second transfer to bring the total of his deposit to 0.001
BTC.