Well first, if you're having pixel issues, just message me because it can be very difficult. But secondly if your pixel is installed on the website but you're using external forms or something form your crm etc thats not tracking. If you have a page that they get sent to after filling out a form or making a purchase like a thank you page, you can just use the code snippets from this page and add the relevant one into the head code of the page they end up on.
So if they fill out a form and your pixel isn't picking it up, but they always get sent to say a thank you page, copy the form submitted code chunk into the head of the thank you page and then your ad manager will trigger the form submission from the thank you page being landed on