Paint Job defects

Good day,

I bought a brand new car 4 months ago at Hyundai Bryanston.

The car has been showing a defect on the bumper paint that keeps on spreading and at present it is all over.

I had reported this case to the dealership and they have been saying they will call me back to come to the dealership again so that they can sort it out.

I called the headquarters in bedfordview to lodge a complained and they did not even call me back nor provide me with a reference number.

It has been a month now trying to call for assistance and all they say is they will call me back.

I do not understand why would a brand new car have a paint job issues already in 3-4 months?