Only part of the order without any postage charges is being exported and imported into new website.
Order numbers aren’t even the same.
The only thing that is correct is name and address of customer
As per our communication via support ticket, we have tested you CSV and imported it without issues. Please try importing as per the mapping shared via the ticket. The issue might be because of some wrong mapping. Ensure that you are not mapping any columns in the CSV to more than one field during mapping. You can only import one column to one field.