Email to customer.

How do I stop the email confirmation being set to the customer after a form is submitted?

I have sent up my own email confirmation with active campaign   

If I understood your concern correctly, you would like to remove the autoresponder being set up that is sent to form submitters after their form submission. 
I have checked your account and I was not able to see any autoresponder email that is set up. It seems like you have found the solution as well. 
Here is a guide to remove autoresponders:

 If this was not helpful, could you please provide us more detail about your concern?
So we can assist you better in this way.