Yup. This is literally just a cellular grey route site for some shitty VoIP provider, just like the SIM box SMS scams go marching on in other countries. Some operator is shitting their pants right now, probably.

The SIM cards come from cheap MVNOs that have dealer arrangements for cheap or free first month activations, then they just set up a handful of SIM boxes and a residential Internet connection back to the mothership (like they did at the captured house with the white Verizon 5G Home router just casually sitting on the floor next to the units).

Similarly, I’ve had some friends on US MVNOs themselves that have access to “free” international calling, yet every time they call (the same) international number the receiving party gets a wildly different caller ID from a wildly different country each time (Poland, Moldova, etc). Also dodgy SIM boxes!