Repair of Damaged phone

Last year I bought a LG G4 from FNB and I have been using it for about 6 months. Last week my phone just shut down and never went on again. I contacted FNB and they said they would log a request with the courier company, telling me that they will contact me within 48 hours. I called three times after the 48 hour period and I was promised that the courier company will collect the phone to repair it. They also promised me each time that they would call me to follow up on the query. Im still waiting for my phone to collected so that it can be fixed. I dont know what to do anymore.Its frustrating calling over abd over for the same thing.