I am using Particle electron and i have around 20 devices with particle SIM card, before the outrage it was ok for me , but now things get really expensive and i raised that before, however i just looking for any idea or something i can do to reduce the cost of these 20 Sim cards, as i pay $2.99 for each sim and extra data consumption which now is really high, i got a bill this month in TOTAL of $166.84.
have you raised a support ticket just in case something is wrong with your devices?
knowing nothing about your setup does not help to provide feedback, but what if you looked very closely at your code and find out where exactly the firmware consumes bandwidth? Doing this will allow you to try to control the data consumption a bit better perhaps?
I remember some time ago an acquaintance was receiving high bills and they were inadvertently calling a 3rd party site almost at every loop time (this was a library that did a direct tcp connection so they were not limited by the particle cloud).