PaulDavis I'm very happy for the help received, I really solved my problem in theory, I didn't know there were those solutions.
Out of curiosity, the CS of what precisely? Are you saying to top up my SIM in the O2 shop for example? (in addition to news stores?)
Proton is blocked in all those countries that need to have deep control of every movement you do, especially on government based services, which can even be your hospital (which forces you to share details here and there despite I signed NO), so it seems that Proton is not so willing to cooperate in case they need to :D , or someone is trying to prevent the usage of it so no issue at all :) .
Moreover I wonder if Proton blocks accounts that connect over tor, but it would be silly after the registration because you can still hit the webserver :D .
Regarding the details, I don't want to mention it for a specific reason, sorry, I again underline that I appreciate all the help provided here, now I have something in my hands.