How to unlock Telstra 4GX Plus (Huawei E8372h-608) modem?

I bought Telstra 4gx plus modem from the Good Guys few months ago, and it is locked to Telstra (I have tried inserting Kogan sim in it).
Any way I can get the unlock code without getting charged $25 from Telstra?
Any chance of an eBay link?
Have you tried unlocking by other means?