abs fault ?

My peugeot 307 has had new breaks pads and discs front and back on 03/08/06. I have had it servieced and the garage now say that it needs the back ones doing again due to corrosion again. Is this a common problem with peugeot and is a average life span for pads and discs? I have only had the car since may this yr. Do i have any rights to complain to the garage where i bought it from and they also do the service??

I am also getting an abs fault showing on display can this be connected to the breaks or an electrical fault