Your Shift72 platform converts all subtitle files to ".vtt" format. Therefore you will have to use WebVTT styling cues to style subtitles.
You can use this website https://chromecast.smplayer.info/convert-srt-to-vtt/ to move subtitles to the top
Here are the steps :
Upload the SRT file to this website
Set the "Encoding" as "Western European language (ISO-8859-1)" (This can change depending upon what type of encoding profile you want to choose)
change the "Position of subtitles on screen" value, the number it is changed to will affect where on the screen the subtitles show up. 0 is at the top, 100 is at the bottom, and between these values will be between the top and bottom.
Output format --> Choose VTT
Now upload the converted VTT file to the movie.