I have been in a situation like this before.

Advice #1, dont make financial arrangements with people "covered head to tow in tattoos who act like savages". They either have the money or they dont and if they dont, come back when you do.

He put money in your hand. If he wanted an option of a refund or a particular time limit to pay you, he should have requested something in writing. I assume no refund was ever discussed, he isnt entitled to one. You dont owe him anything. I would tell him to open a claim if he feels he is entitled to financial compensation.

Him threatening you is a completely different issue that is completely separate from the financial exchange. Even if you broke into his house and stole $2000 off his dresser, that wouldnt make it legal for him to go vigilante and come to your house and attack you or damage your property. If he feels he has been robbed or cheated in any way, encourage him to call the police and let them sort it out. They will inform him to open a claim.

I would cease from contact with him and report all threats to the police. If he opens a claim, appear, tell your side of the story as well as the threats and actions that he took.

Lastly, if someone is an immediate threat to you or your family, protect yourself and your family. I would invest in a camera, seeing as how property damage is the most likely result of his retaliation.