Complain for phone

I would like to lay complain against the exact shop, i bought the phone on March 2019 and few months later my phone started to over heat and went off automatically, I've tried to power up the battery still not working. I took it back to Exact in Johannesburg CBD, and told them i required the partial repair, their technician must not worry themselves about the camera though the screen is cracked and it still working. The main concern is that phone is not switching on. When i call their technician they told me they will send me the quotation for the repairs and they don't do partial repairs. Exact sales lady told me that they shouldn't have quoted me as the phone is still in warranty.