Also, for transparency, this is the email I just sent to them.

Just to address your points one by one, I am able to prove that I still live and reside in Luxembourg and I can provide  rental agreement, utility bills, residence permit and even employment contract that will prove that I not only was living in Luxembourg at the time of opening the account, but I am still living in Luxembourg. I am also happy to share my utility bills for the months of June and July (when available) to prove that I am still living in Luxembourg.

The reason I do not use Wifi on my phone is that I spend a lot of time at work where the Wifi is capped (cannot access many sites such as youtube), therefore I always keep the Wifi setting off on my phone, given that I have unlimited mobile data anyways this has never been a problem for me.

Additionally, I would like to point out that allowing me to complete an exhaustive KYC will shed light to the questions you are asking and will clarify where I was when using the Rollbit account.