I think you are referring to Heli Malongo. They took delivery of their 1st Q400. Operating -300s already.
Heli Malongo flies "long haul" shuttles from LAD to remote places on mainland from where oil workers will proceed by heli to the oil rigs.
Heli Malongo is a subsidiary of Sonair which is the air services company of Angola's state oil company Sonangol.