Complain about panelbeaters

I took my car to SANDTON BMW AUTO REPAIR CENTRE to be panelbeated after i was involved in an accident. (07 May 2019) On Monday 07 October 2019 while reversing I hit the pole the same spot where it was damaged,I was shocked to see how the damages on the car were previously fixed,seems as if they put polly filler or plaster of paris or cement,i really do not understand, all the panelbeaters i visited were shocked and tongue tied when i told them the BMW are the one who did this job. Please intervene. Thank you.