Can i add my username here? If i can, what amount have i to put in the field?
My investment was 50$...
If you invested USD the you should have already received your money. The payback is only for people that invested bitcoin and haven't received back what they invested yet.
No, i haven't received yet.
I sent a PM to the admin on last 16th June, but he didn't reply me.
So, now what should i do? Am i the one in this situation?
That's pretty much it mate...just sit back and be patient...BTC-Arbs doesn't respond to anyone until the time he's ready to start making payments for a particular person's claim.