Iced Brown Sugar Shaken Espresso

I own a small coffee shop that recently opened. I have been attempting to add iced shaken espresso to my menu, however I am having issues with my shakers. I got stainless steel ones from amazon. They expend and I’m not able to open them. And the plastic ones were also a disaster. I have played with added more ice to the shaker but still am having issues. Do I need to invest in better quality shakers? Any insight would be appreciated.

Cheers!