Unlock O2 Huawei E8372 dongle for use on other networks

[r1chy23]

I have a Huawei E8372 4G dongle I purchased from O2 in 2017. It still has the O2 pay-as-you-go SIM card, but I would like to unlock the device for use with other networks.

How can I do this?

Thanks.

[Enlli]

Guide: Unlocking an O2 phone to use a different SIM card 

[r1chy23]

Thank you Enlli. I filled in the form via the link so hopefully will hear something back soon.

[r1chy23]

Unfortunately, I've had an email back from mycarewebform@o2mail.co.uk (a no-reply address) saying that my request has been rejected as I have not passed security checks. I can't remember the password from 5 years ago so I seem to be at a dead end as the 'forgotten password' option asks for my last bill details which I don't know either!

Any further ideas?