I think you can login directly within netcut for android use same username/password as you post here. if you see login failed, please try to reset your password. you need a PC to access the reset password link http://www.arcai.com/wp-login.php?action=lostpassword
Also, when you buy membership, it should automatically enable your Pro member after payment.
let me know if you still having issue. you can send me screenshot of errors in case it helps. email at [email protected]
have you tried to login use same login/pass ? it is linked together. I guess there might be typo when type in pass on phone. reset pass overwrite to be sure they are same.