Hello,
It's highly unlikely that the device failed from natural wear and tear after such a short period. Perhaps it could have sustained a shock in shipping or was stored incorrectly.
This happened right after my RMS credit expired. Is it related to RMS?? It would be very concerning if RMS credit and router performance are related.
RMS is in no way related to the functionality of the device, thus this is just a coincidence.
Also, in the original question you mentioned that the 3 LEDs near the power LED were flashing. Does this behavior change after some time or do they keep constantly flashing? If they keep flashing, the official documentation suggests that "No SIM or bad PIN" could be the cause, but if the Ethernet ports, as well as the WiFi are not working, I doubt this is the case.
Lastly, I'll ask you to perform a factory reset by holding the reset button until all signal LEDs light up and then release. If the same behavior is present, please return the device for RMS repair.
Best regards,
DaumantasG