vodacom repair shop cresta poor service

I received terrible service at Vodacom repair shop Cresta, I bought a samsung a5 on the 1st March 2015 and not even 1 month later the phone broke, I toke the phone in and its been in the repair shop for 4 weeks without any answers about the phone and when we went to the shop and asked for the manager they directed us to someone who clamed that he was the manager and later on we only found that he wasnt, eventually we found the manager the quoted me R2600 for a phone that isnt even a month old. It should stil be under warranty. This is truly poor service and we need answers......