For signing up, you need to use a mobile number from a country where Revolut is availabe. (A Moroccan number won’t work.)
If you already have an account but you won’t get the text message with the security code, you can wait a couple of moments after trying to log in, and on the welcome screen appears a link “didn’t receive text” or something like this appears. Tap on it, and support can help you out.
When I understand you correctly, you already tried to log in numerous times and the app now tells you the number is blocked? I can see that this is for security, to protect your account from someone loggin in with your number. I don’t know this, that’s just a guess.
I would try to contact them on Twitter tomorrow during UK business hours. Only support chat is availabe 24/7, social media isn’t.