iPhone trauma, Telkom a no show for me

I bought a phone that clearly had a factory issue. I used the phone about 3 months before the batttery swelled up. I took the phone into the shop and it was taken for repairs. I then received the phone back and used it again. Now the phone just restarts randomly and loses connection. There is surely something wrong with the phone, from the factory, but the shop insists I should have taken up insurance for me to receive any meaningful help. Could it be that these shops are getting kickbacks from insurance brokers, and so they sell us knockoff phones. See me buy an iPhone ever again, kill me.