Unprofessional, callous ground staff, useless complaints department

I fly Airlink a lot and have had may positive experiences so it gives me no pleasure to relay this incident. I booked a return flight for my son to Lubumbashi. On checking in the ground staff refused to give my son his boarding pass unless he changed his return flight to match his visa expiry date. This despite it being quite standard and normal practice for passengers to apply for visa extensions once in DRC. In addition, when I wrote a complaint, the "investigator" took the ground staff's denial at face value - all I asked for was to re-instate the status of my ticket so I may make another change! Extremely unprofessional and unhelpful. I find it very upsetting that they seem to have no care for their passengers whatsoever. If I could stop using them, I would. Buyer beware.