Umkai building and civil works fruad

We subcontracted for Umkai building based in Milnerton, Cape Town. Completed work for City of Cape Town on behalf of Umkai, few clinics and Greenpoint stadium which City signed off. It's a month later and Umkai hasn't paid us, rejecting and ignoring our calls, emails and visits - they are dishonest, unreliable, no professional work ethics. I'm currently seeing a lawyer regarding this matter. To all major companies, please do not hire them as they cannot be trusted.