Unhappy customer

We saved for years to embark on a renovation which included installing a new roof on our home. We paid the owner of Nile Blue Projects, a large amount of money upfront for the building, labour and all the roofing materials. After starting the project, he confirmed that he had bought all the roofing materials but would only deliver them once the building work had been completed. The project started off well but then ground to a halt as materials were not being delivered to site. We scheduled meetings to discuss progress, and the owner never arrived for the meetings. We then asked for the roof material invoices, and the owner blocked our numbers and absconded with all our money. He then communicated via email and said that he owed us the money and would pay it back by a certain date. He did not honour the dates for the promised refund and to date, we have not received a single cent of the promised refund. We are now left with an unfinished building, no roof and a huge amount of debt.