All I can see in the internet are illegal repeaters, since they don't have NTC approval in the form of NTC sticker.

So now, where can I buy a legal signal repeater? In our province, the signals only exist at high altitudes (which we can get if we place our home wifi modem on a pole and raise it higher than our roof). Down on the ground, wala talagang signal, so we can't call, text, or receive OTPs. For this reason, we need to be able to receive these signals down on the ground. We don't need to boost the 2G signals, we just need to be able to receive them on the ground. Do you know where I can buy legal signal repeaters for this purpose?