Welcome to Shopify Community.
Aibek is here from Speedimize.io
You have an error after connecting the Stamped widget on the product page. http://joxi.ru/nAyB07aIgn343r
There is no opening tag <script>
After this text <!-- Stamped-End Main Widget --> write <script>. After that, it should work.
As a result, it should look like this: