I know we're only hearing one side of the story, but assuming you're accurate I genuinely hope you get paid. You didn't say how much you were owed, but I am guessing it's a few hundred quid.
However, just a couple of things I would consider;
Firstly, HASSLE.
Do you need it? Do you really want to spend your time, energy and of course money chasing someone through a legal process for this money? Very infuriating to not be paid, but it's good to take a step back and take a dispassionate view of whether it's worth your time and money. Time you could be spending furthering your own business. Sometimes it's a matter of putting it down to experience, and moving on.
I once heard some great advice from a Barrister on TV a few years ago, he said "If you find yourself saying 'it's the principle of the thing!' that is the time to stop your legal action".
Secondly, CAN HE PAY?
We don't know the circumstances, but could it be that he had every intention of paying you, but then things happened that meant he simply couldn't. You said he was desperate, maybe he is in the midst of some unfolding crisis?
Is taking him to court (or threatening it) going to enable him to pay? If he simply has no money, no court can help.
Whatever happens, I hope you get it resolved!