Howdy Phillip,
I would love to help you with this.
I am running Google Chrome on Windows, and am also having trouble updating the # of tickets in my cart on your website. No JavaScript errors are being shown, which means we will need to test if a “conflict” is happening, and if so narrow it down so we can find a fix for it. This guide walks you through how to test for a conflict, and then identify what is conflicting.
You might also want to ask users who are having trouble adding this to the cart what browser/OS they are using. It is likely they are all using one browser, such as Safari, and the only way to reproduce their issue will be in the same browser.
One thing that might impact this is to setup your permalinks in WP-Admin > Settings > Permalinks. Yours is currently set to “Plain”. You might change it to any of the others, such as Month and Name. This will essentially turn pretty permalinks on, and can sometimes fix issues in WordPress.
Does that all make sense? Will that work for you? Please let me know.
Cheers!
– Brook