Just got another reply from the Rollbit team, they seem to not want to budge at all, as they won´t accept any proof I can provide. They don´t even accept to do the short notice video KYC as @holydarkness proposed

At this point I think I am left with very few options. I though that maybe I could just send them over all the documentation through the email communication to prove that I am still living in Luxembourg (even though they have not asked for it), maybe this will persuade them.
From their email, it seems like their TOS are heavily skewed towards the website, how is it even acceptable that my winnings in Luxembourg are void and the whole account is closed down because they believe I am moving to a restricted region?, even if they understand that my winnings were from an unrestricted region like Luxembourg. I would understand if they warned you about connecting from unrestricted regions and gave you the chance to withdraw the funds given they are not regulated there - but outright closing the account and keeping all of the funds? It seems they are looking for any and every way to steal player´s funds.
I am running out of ideas, and maybe the most clear option is to contact a lawyer in Curacao to help me with the issue.
@Pmalek, I am looking into the GSM triangulation but my phone providers are yet to come back to me with any details, will let you know.