Unable to Update Slider Revolution (Betheme)

I have been trying to update our slider revolution plugin that comes as a part of our Betheme, theme.

It currently refuses to update using the following methods:

Updating Via the plugins Page on Wordpress gives the error: PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature

Updating by downloading the Zip File containing the theme from themeforest downloads page. This does not contain the plugins folder.

We follow the API Link: https://api.muffingroup.com/plugins/download.php?code=XXXX-XXXX-XXXX-XXXX&plugin=revslider
from the Wordpress page manually and receive a completely white page.

These are the 3 methods that I have researched and tried and none work any suggestions or help is appreciated.

Get some support from the item author: