LG is not being loyal to its customers

I took an LG G4 cell phone via FNB on the 30 July 2015 at East Gate Mall, the phone was working perfectly fine until the 23rd of December 2015 it didn't want to switch on until now I have been sending them emails but no response from them, I don't have a cell phone but the cell phone has 2 year warranty but no assistance from your team up to now and its been 3 weeks since I don't have a phone. Who must I speak to because customer service told me to take my phone to my network provider but I went there and they want me to pay. Assist me regarding my phone because this is in appropriate and its not good for your reputation as well since am writing here for your attention.