Sanuki Corporation Japan. review: Purchased a truck that had already been sold.

Purchased a rubbish truck in 02/02/2026 with 2 invoices totalling $16,790 USD. Couldn't Supply. I flew to their business and discovered it had been sold many months before I paid in full. They said they could supply another one but had no idea what they were supplying and I was offered a completely different chassis family, which was too big for my application. I have been arguing for a refund since March. they offered a reduced amount which I accepted to get on with my life, but they are refusing to pay that. Lawyers and the legal system in Japan appears quite weak. $15,390n is their offer but these slumdogs are still not moving. Can you help?