I have done so much research https://www.behance.net/300CDesigns And so far No idea if legitimate or not. From some points of view, it sounds sit going well, but at the same tie he is based in the UK with A Russian name (I think)
Half payment has been sent but what made me look into it he is asking for another part of the payment saying " kind need some cash on my bank ;DD "
If the two of you have already agreed to a sum amount which half is paid up front and the other half paid once finished, don't give any more money until you can see some finished work done
I'm going to lock this because I don't think it's a good idea to discuss potential trade disputes publically.
I'd suggest speaking to them and asking for their progress on any work you've paid for and if they want more money then you may need to speak to whatever payment provider (like PayPal) you've used to raise a dispute.