LG G2 f320 only 2G topic

Hi guys, I have network problem with my LG G2 f320 (korean version). I have T-Mobile Czech Republic but I can use only 2G/gprs. In the notification bar I have 2G icon mostly time,sometimes there is 3G but not received/send data (arrow next 3g icon doesnt light) . 4G doesnt work. In the network settings is only choice between "wcdma only" or "automatic" . Please do you have any idea where should be a problem? Thank you very much
I have Android 5.0.1 (with older versions it didnt work too)