I remember unlocking my Mobley SIM and changing the lock code from default, then moving the SIM to the netgear hotspot router, it's been on pretty much 24/7 ever since then, runs on battery when the inverter and/or generator are offline,
I bought my netgear 815S in June 2018
I think Feb 2018 thru Sept 2018 will have the most postings about the Mobley SIM to Netgear , service, sims, etc..
I can't be sure on the date but I think it was Feb 2017 when I gof my Mobley and started service, possibly even 2016
Will have too look up my AT&T account for start of service date, when I'm less tired and more awake,