Password may have a range of {6 to 15} chars,
and must consist of at least -
(i) an uppercase letter,
(ii) a lowercase letter,
(iii) a digit, and
(iv) a special char amongst
! @ # $ % & * ~
Mobile must consist of exactly 10-digits, first digit of which may range
from {6 to 9}. Further, a user must enter a valid email address to receive
the OTP via email.