LG G2 4G LTE (D802T)

Hello everyone I have recently purchased LG G2 D802T. In my country 4G is recently launched (Pakistan) but in my mobile while trying to search for networks it has only GSM or WCDMA (No LTE). MY question is that how I can get LTE, permanently. Yes PERMANENTLY as I have already tried several codes, they do search for LTE.but when I open the settings again then it comes back to original I.E. NO LTE. So please help me and also tell that if I need a new SIM for 4G. Also is I need then at least my device should show LTE option because it is written on its box 100% LTE.