'You are eligible for referral program' message at checkout - where and how do you edit it?

We’ve had a few customers mention we have a message once fully checkout (order confirmation) that they are eligible for a referral program and to refresh the page to get the referral link - we do not run any type of referral program and I am at a loss to try and find this rogue block/code - I have looked everywhere (…everywhere I know!)

Any ideas?

We have recently moved over to Ella Shopify theme so I could raise a ticket with them but thought would ask here first?

I wish I knew! It keeps appearing on my checkout as well, and I don’t know how to get rid of it.