Line 6: usename is a single char. Assuming you're entering more than a single character, the remaining characters are going to remain in the input buffer.
Line 11: Since there are characters available in the input buffer, this statement removes the next available character (the second character of whatever username you entered).
Line 13: Again, assuming characters are available in the input buffer, the getch() will be satisfied immediately.
Change your declaration of username and password to character arrays of a reasonable length.
If you want to keep them aschar though you could also usecin.sync(); after each input. However if you want to use several characters instead of a char array with a definite length perhaps use a string instead.