The ornamental design for a protectivecase for a telephone, as shown and described.
FIG. 1 is a perspective view of a protective case for a telephone showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom view thereof.
In FIGS. 1 and 2, the unshaded surface and the broken lines thereon depict an unclaimed telephone. My design includes a second embodiment of a protective case for a telephone that comprises a mirror image of the embodiment depicted.