Is your POWR plugin not working on Bigcommerce mobile? This may be because Bigcommerce Mobile Themes have separate controls.
If you're using POWR Plugins on your Bigcommerce store, you've already added the POWR Script to your HTML/CSS file. If your Bigcommerce store uses a Mobile Theme, you'll need to add the same POWR Script to the Mobile Theme as well.
Check out the Bigcommerce tutorial on Customizing the Mobile Theme.