Faulty phone/ no exchanges!

I upgraded my contract on Thursday 13th Sept and took my new LG Q7 home and started customizing my phone on the 15th Sept (with apps I use daily) Customer service is not great at this store, by the way...

The phone's battery kept getting HOT and it was drained by 1pm. I was unimpressed. I took it back to them the afternoon of the 15th and they said they would send it to be tested. Today they called me to say they did in house testing and everything is fine and the phone has a scratch on it so they won't send it away. I have used my old phone for the last two years that hasn't once had a problem with battery temperature (my son uses it constantly to play games and it doesn't even get hot!)

I'm very unimpressed that they haven't sent the phone away for proper testing and now I must sit for another two years with a faulty overheating phone... When I queried this, I was told that they would show me the fine print in the contract I signed. Shocking. I don't want a faulty phone!