Band Locking Netgear 4g LTE Modem

Hi have just purchased the LB2120 modem after reading positive reviews about it. My modem is locking on to the weakest 4g (700mhz) signal you could possibly have and ignoring the 3G (850mhz) which is booming in. I’m in a remote rural area using an external yagi antenna at 12m height. My old Telstra 4g Advance modem has 3 signal bars all the time and while it too has 4g/3G capability, it seems to know what to do with the weak 4g signal....ignore it.

How can I lock my LB2120 to the 3G bands only please and block out the others (LTE).

if this cannot be done then I’ll be very disappointed in Netgear and deemed to have wasted my money as it’s no use to me like this.

please help!

thank you