You can test yourself and see if the payment is working, if it does then its working 
What you need to do is use google analytics and see what the users from tiktok is doing after landing on your site, are you closing the page as soon as they come to your site, are they navigating to any product.
In case they navigate to a product, check if they are scrolling down to product details or not.
You need to improve your site if they are not buying.
Also check from which country they are, add chat to your page so they can write to you etc.