Hello Amit,
Does the Product Page you create use the same Template, and is the product of the same Page (Document) type, as your other products? You can find out in:
Properties -> Template
If the templates are different, try using the same one as your other products.
Properties -> General -> Type
If the product type is different, please verify that if you using a macro in the the Selected item transformation property of the Repeater the transformation of that code name exists in the Page type definition. I.e.: if you are using a macro like this: {%classname%}.CorporateSite, ensure that the CorporateSite transformation is defined for your Page type
Kentico does not feature the ability to export individual Pages. If you need to export content, you need to export the entire site at once. I recommend setting up Staging if you need to synchronize Page changes between two environments.
Alternatively, you can use the Kentico Import Toolkit to import raw product data from one Kentico database to another