Left my suitcase in the bus. Company have no complaints contact details

On 15 March 2020 i travelled from Beaufort West to Queenstown for 4 weeks training. The bus left Beaufort West at night 23:00 and arrived at Queenstown at 5:00 am. When i arrived at my destination I realized that my suitcase with my clothes in it i left it in the bus. I tried to call them to report the matter but they don't have any contact details for complaints. Up until today I haven't received my suitcase. Their service is poor