I positioned my subtitles at the top of the screen. When I do a playback using the VLC player to check on the exported SRT file, I still see the subtitles at the bottom. What am I doing wrong?

SRT files only support timing and text. They don't support positioning of subtitles or other layout features, so that information gets lost when you export. Depending on the application that you use, you could try ebu-tt-d. 

Note: the ‘cell resolution’ that you’ll find in the Automatic Subtitler Spotting Rules (here), will also only be effective with the ebu-tt-d.