GREYHOUND REFUSE TO REFUND ME WITHOUT REASON

I purchase a return ticket from JHB to CT on 08 March 2024. Booking date for return from CT was 01 April 2024 Booking Number GHAJ47702 However I had to leave earlier and cancelled the above I request a refund telephonically on 29 March 2024 and submitted form on 05 April 2024 to "*** and "***" I receive no acknowledgement and I had to call to confirm if it has been received only to be advised their system is "off" so I re-submitted with a complaint of their service on 30 May 2024. After numerous calls to *** with no resolution. It is now Jan 2025, again I called 17 Jan 2025 at 13:47 spoke to Siyabonga Makoba who promised to escalate the mater which was escalated before by Bulelo Kwani on 14 July 2024. What should I do open a case of ***** against Greyhound to get R685.00 refunded to me?