Thanks mate! I contacted them it's much more expensive than that.
Anyway I posted here hopefully anyone else knows a solution.
Quote from Pack & Send:
Oh yes, and I recently switched to an Optus (non-Amaysim) 4G plan. The OnePlus One works on LTE, but it can't connect to data as reliably as the iPhone 6. Sometimes where the iPhone can connect instantly, the OnePlus One takes forever. It shouldn't be a problem if you keep data on all the time, but I prefer to turn it off when not in use to conserve battery.