The ornamental design for a teepostmountingdevice, as shown and described.
FIG. 1 is a front perspective view of a tee post mounting device showing my new design, wherein the features shown in broken lines depict environmental subject matter only and form no part of the claimed design;
FIG. 2 is a bottom view of the same, wherein the features shown in broken lines depict environmental subject matter only and form no part of the claimed design;
FIG. 3 is a top view of the same;
FIG. 4 is a right side elevational view of the same, wherein the features shown in broken lines depict environmental subject matter only and form no part of the claimed design;
FIG. 5 is a left side elevational view of the same;
FIG. 6 is a front elevational view of the same, wherein the features shown in broken lines depict environmental subject matter only and form no part of the claimed design;
FIG. 7 is a back elevational view of the same, wherein the features shown in broken lines depict environmental subject matter only and form no part of the claimed design; and,
FIG. 8 is a front perspective view of the tee post mounting device wherein the features shown in broken lines depict environmental subject matter only and form no part of the claimed design.