Hi @allampatu,
First, importing tabs is different from exporting.
Second, if you export a file of products (w/ tabs) and then import that file, you shouldn’t lose your tabs. The only way in which I can see this happening is either you didn’t map the post meta field correctly or you somehow manipulated the file and corrupted the tab data (e.g. search and replace, funky character encodings, etc.)
Third, there are a lot of support tickets in which I talk about how to import tabs as well as why importing tabs can be a difficult process and some common mistakes users make when trying to import tabs. (How did you find this 6 month old export ticket without stumbling across all of the other import tickets?)
The best way to import tabs is through WP All Import with our WP All Import Custom Product Tabs Add-on.
Depending on your scenario, there are various other ways in which imports can be achieved.
All the best,
Kevin.