Not adhering to promise of service being rendered

We have registered two of our employees last year (2015) to perform the 'Receptionist and Frontline distance learning program' course. This company were quick enough to reply and accept the registered attendees and to receive the payment in full for the course to be done throughout the year. When they submitted their exams for marking, we have not heard from them since. They do not respond to endless emails being sent to them, and when you try to contact them via telephone there is always a voice prompt saying that they are experiencing communication problems. I found their address (112 Scott Street, Hartbeespoort) and wanted to drive to their location. I did however first phoned one of the neighbouring businesses to find out if they are situated at the address. It was confirmed to me that there is a Security company in that premises. How does one go about resolving an issue like this? I have seen another complaint to involve the Ombudsman, which might be the only route left.