I've been with Three.ie for 10+ years, presently have a Huawei B525 modem and am out of contract since August.
As far as I'm aware, I fulfill all of the criteria that Three requires, in order to allow mobile devices to be unlocked. But when I go through their unlocking procedure, although my Broadband sim is detected as Billpay and I'm allowed to 'proceed', I cannot get past the SMS-verification stage. I enter my number, it tells me that it is sending a SMS with a verification code, to my device, but one never arrives, despite hitting the "resend" option multiple times. There is also nothing wrong with the SMS setup as I can send & receive texts using the B525 via the 192.168.8.1 web-browser thingy.
I'm sure that Three is legally obliged to provide unlock-codes for all mobile devices that meet their criteria, and the B525 is certainly a mobile device.
Has anyone gone down this route before, and perchance arrived at a solution?