I tried a long expiry plan in a GPS tracker and it would not work.
I ended up using a pre-paid ultimate plan. Expensive but it worked.
No idea how to tell which pre-paid SIM plan will and won't work.
The frustration I have is the inability to get SIM card account balances to track usage.
Like I said, I can't say why but when I discussed it with the GPS tracker supplier, they reported the same problem happened with quite a few people. For some reason the long term plans would not work in these particular trackers. As soon as I got Optus to switch the plan over, it worked just fine.