TransactionID problem

Hello
Again requesting your help.
I registered in TradeTracker and I implemented the conversion pixel in the page of thanks to which the user is redirected once he completes the WordPress form with ContactForm7.
But I have a problem with the transactionID value, because I do not know how to pick up the email that the user has filled in in the form to follow up on that value.
The pixel code that I have been given is:
<img src="//tl.tradetracker.net/?cid=xxxxx&pid=xxxxx&tid={}&data=&eml=&descrMerchant=&descrAffiliate=&event=lead" alt="" />
What code should I add between the {} of the value tid =?
Thank you in advance for your help.

The page I need help with: [log in to see the link]