bad service

had a very terrible experience with vodacom, took in my phone for repairs as it had a problem, i then got it back a month later and i was told it couldnt be repaired and they gave me a new phone. it was not even a month later, it was exactly 3 weeks later that my phone died again of the exact problem as the first time and when i went to inquire again i was told that the phone that was given to me was not entirely new and they spun me some story @hellopeter please kindly assist me