tracking customers who have not completed the purchase

Hi,

we have a retargeting campaign set up to target the unfinished purchases with a a free shipping and after that with a discount coupon code.
The problem we ran into is that some customers who completed the purchase saw the retargeting ad (intended for uncompleted purchases). Now the marketing person wants us to check the order complete url as it used as a filter in the campaign set up.

We have used domain.com/checkout/completed/

and my question is is there any other syntax that should be used?
does the slash at the end make any difference?
Any suggestion?

thanks

You can install auto register plugin and allow customers to go to checkout without registration (order as guest).

So, if a customer fills his info at billing address step (even if customer doesn't complete order), then you can track it at current carts in admin and see what products customer is interested in.