Poor Service and Communication

I purchased a brand new Toyota Corolla Quest at the end of December 2018 from Halfway Toyota. I am the sole driver of the vehicle. Recently my vehicle was due for it's 15000 km service. I booked the vehicle in at Menlyn Toyota an once they started working on the vehicle they contacted me to say that the rear brakes were reaching it's life span. I then contacted Sas Botha at Halfway Toyota Honeydew as it was impossible that this brakes could be finished so soon. After doing some enquiries it was noted that perhaps when we bought the vehicle the hand brake might not have been adjusted correctly and thus causing the brakes to wear out faster. In my opinion this should be a product warranty but I am not getting assistance from this dealer on how to resolve this and thus I am writing to you, perhaps someone will be willing to assist.