Poor quality of service received

took my car for service at Lannie motors tzaneen, the person who was assisting indicate as a normal routine she will contact me if any additional work need to be done, after collecting the car within 3km brake pad warning ligt came off, called the service assistant likely since iwas within reach took the car back

The car was diagnosed in the presence only to find out the brake pad fade off and i requested to speak to the manager and asked how did they miss that, the manager is so arrogant he said itwas just an oversight and make matters worse this is my second incident with them, i am paying why should i receive sub-standard service, apparently they are using junior technicians wihtout supervision cause if the work performed was checked by the supervisor that should have been avoided