First of all reviewers make mistakes all the time, so you can resubmit it and very often the second time it is accepted.
If it is not accepted the second time, then maybe there is something wrong.
From what you say the video setting for resolution in your drone are not the same as your encoding settings in Premiere.
Make sure you are using the same settings, for example 4k DCI, or HD

My footage has approved on adobe and pond 5 but not on shutterstock!?

It happens very often, SS have some really bad reviewers.
Simply reupload it, it will probably be accepted