He cannot refuse you a refund. He agreed to a payment plan, had no terms that said a refund would not be given, and was expected to give you goods that he has now failed to give you. He has two options. You need to tell him that he either refunds you your money right now, or you will get a lawyer and take him to court. You would win. Hands down. Especially if you have any sort of paper trail (emails, receipt of payment, etc). How did you pay him, if you don't mind my asking? You need to contact whatever institute you used, whether it was a Bank or PayPal, and explain to them what happened. Most of them should work with you.

Pretty sure that him holding your money without rendering the goods paid for is illegal. Just saying.