I'm a new business owner and my tap & Chip card reader disconnected four times in one day! I'm not sure if there is an issue with the card reader nor am exactly sure what the problem is. I've looked literally everywhere for a Shopify customer support phone number and have been successful.
I am having the same issue since last week. Did you ever receive a response? We're having to take the reader out of its holder, turn it off, "forget" the device on the iPad and go through the whole repairing issue. Not great with customers waiting.
And I have been able to catch Shopify via Chat Help a few times. I can't remember how i found it but I stumbled across a chat option and that led to an email exchange.