Poor service from Natis Online Services

My Drivers License are about to expire and would like to be pro-active in my approach to book via Natis Online Services an appointment. Through numerous attempts I am not able to find a slot. I have called their Call Centre on ***and waited for 30min just to be informed after moving down the number waiting that the person I am looking for is not available. This is poor service and am unable to renew my license.