Bad service unsatisfied

I bought a karimor back pack for my daughter at the Caledon branch, last year April I went back as the stitching started caming loose, the store exchanged the backpack after consulting with their head office, November last year after 5 months the second bags stitching came loose at the same spot, surely this is a quality issue, I took the bag back, and informed them that the quality is not right, the manager took the bag and told me he will engage with his head office after a week no call, I had to go back to the store to find out what is the status. He told me that his head office declined the refund, because according to them this is wear and tear, I logged the complaint with the call center 2 weeks ago, to date nobody came back to me, thinking if the call center actually logged the compliant, how can a life time bag, break in 5 months, and than the feedback is wear and tear, the lady geniviwe, still didn't respond to my complaint R499 later, I need a response and feedback