He is a ****mer

He is a ****mer. He was contracted to build a nutec house, Wendy house and septic tank. I asked him if he is NHRBC registered and he said he is but he needs to renew his membership. I needed proof of this. He then asked for a deposit as he couldn’t apply because he owed SARS money and can’t get a tax clearance so I paid him in total R20k this was over a week ago. I then asked him to build the Wendy house so long and that I decided to move to someone else for the septic tank. Now he keeps on asking more money and says it’s R7000 for transport and he cannot do just the Wendy house etc. I’m getting only excuses and no joy. I’ve asked him for a refund or the Wendy house.