Samsung S3 Screen defective

They repaired my phone screen for R1550.<br> Four days after collection no working screen. <br> Now the agent tells me no guarantee on screens. CAN you believe that. Whilst I'm trying to speak to this person he just keeps on playing his cellphone game (pool).<br> <br> I'm also of the opinion they gave me somebody else's phone (no Im nr available on phone).<br>