Max BR1 Band Questions

when i choose band 12, i get the following link numbers:
LTE Band 12 (700 MHz)
RSSI: -65dBmSINR: 0.0dBRSRP: -89dBmRSRQ: -12.0dB
However, my ping times are non-existent - i get 5 bars on Modem but i can’t access internet. If i switch to band 4, i get 3-4 bars and internet access is ok. Why can’t i use band 12?