No final boarding call - missed flight

Me and a colleague were supposed to depart from CPT to DBN on 6 Aug 2015 at 6:30 (flight BA6301). It was then communicated to us that there is a delay due to a hydraulic leak of some sorts and that the flight is delayed until 10:00. This meant that we already missed important meetings scheduled for the morning. After being denied access to the slow lounge (even though we spent R15k on the tickets) we went to sit in the Mug & Bean. At 07:40 we went to the screen for an update and suddenly (to our shock) saw that the flight was already DEPARTING! We heard NO boarding call and NO final boarding call specifically calling my colleague and I. So we missed the flight. We then went straight to the British Airways counter (seeing that we would have flown with them) but they just pulled up their shoulders and referred us to the [URL Removed] counter (which is NEXT door and part of the same office space). The [URL Removed] people then at least gave us another flight at 10:35 free of charge, but this is NOT good enough. Comair FAILED to call us, we are certain of this. We went back to the M&B afterwards and HEARD boarding calls VERY clearly. I await feedback from Comair - this is unacceptable.