Urgent: Issue with WebKit users adding to cart. Don't know what to do.

[lovehockey]

Hi, 

I have installed theme Sense (updated to 15 from 8.01 yesterday). I use a number of add-on apps, naturally. 

Recently (last 30 days) I noticed users who come to the store try to add items to their cart repeatedly become enraged because they are repeatedly presented with an empty cart and leave. 

It only happens to users using WebKit (a version of Safari on mobile). 

I've been doing searches online and found something about interactivity between some add-on apps and Shopify where this may have happened to others too. The problem is I'm not very technical so I'm not sure how to look at the raw code or where to even look. 

Can somebody help please?