Dissatisfied with Admed Gap Cover

My parents are pensioners. This is the second time they are claiming from Admed Gap Cover despite paying for so many years. My mum has been to hospital to have a stent done. There was a small portion medical aid didn't pay. I sent that to gap cover with all the supporting documents which they requested for. Then gap cover sends a list of what they do pay for and unfortunately cannot pay the shortfall. My knowledge of having a gap cover is when medical aid cannot pay, gap cover pays the shortfall. Then why pay for a cover, when in time of need there is no help. I will not recommend Admed Gap Cover to anyone.