Damaged goods

Hi, I bought my phone blackberry Z10 last year may at Edgars, I use the MTN network, In August my phone gave me a problem and I took it to MTN repair centre and they gave me a refurbished blackberry Z10, now the same phone is giving me a problem, I need to find out am I really going to loose my money because blackberry sold me a problematic phone or will I really get assistance. I would like to have my money back or have another phone.*** / *** Miss Kubeka