cheap service by an expensive private hospital

my father was admitted at our local netcare hospital N17 in springs on the 26 of April then in the early hours of the 27th around 4am which is not vising hours , came in a stranger in his room claiming to be sent by my mother to check on him which was not true the man is unknown , my concern is that how did he get access as it was not vising time and there is 3 security guards to pass before entering the wards , when the matter was raised with supervisor she came up with excuses not wanting to take responsibility and acknowledgement that they opened for a complete stranger and didnt consider the safety of the patience, her words where " it is not negligence that patience go out for a smoke and leave the door not properly closed, the stranger was already in and asked to see the patient we had no other choice but to just let him go through after all he was already in and he didnt even take 5minutes with the patient we cant blame the staff or take responsibility" iam complaining because we put our safety in the hospital when we are in our sick beds and such negligent is shocking in a private hospital my dad is a non smoker why should he be unsafe because of "smoking patients " the stranger could have bin anyone , a ***** or someone who wanted to **** him. iam getting tired of this hospital they had 1st given my mother wrong meds which almost ****ed her the very same month April 2018 and not handled the admin well. why should we be in an expensive hospital for cheap service . i would really appreciate if my complaint can reach them.