Quantity selector problem

Hello, I’m using the Refresh theme on my store and I can’t get my quantity selector to display online even though it’s activated in my theme settings.
Shopify support told me to turn to you. It would be a line of code to add, but I don’t know anything about it.
Could you help me?

This forum is for developers building with our APIs, your best option would be to post on the merchant forums here: Technical Q&A - Shopify Community