The ornamental design for a case for mobilephone, as shown and described.
FIG. 1 is a top right side perspective view of a case for a mobile phone according to the present invention with the hold down strap in a closed position;
FIG. 2 is a front view of the mobile phone case of FIG. 1;
FIG. 3 is a rear view of the mobile phone case of FIG. 1;
FIG. 4 is a left side view of the mobile phone case of FIG. 1;
FIG. 5 is a right side view of the mobile phone case of FIG. 1;
FIG. 6 is a top plan view of the mobile phone case of FIG. 1;
FIG. 7 is a bottom plan view of the mobile phone case of FIG. 1; and,
FIG. 8 is a top right side perspective view of a case for a mobile phone according to the present invention with the hold down strap in an open position.