Sync Drupal commerce order information
Some general advice: 

I had a similar situation on a project. I first tried various options for importing orders from the separate sites into a central site using modules like:


commerce_order_ftp_export
commerce_export
commerce_export_csv
commerce_feeds with patch for orders


But you will need custom code to resolve order IDs etc. Depending on the number of sites, this may be workable.

However, I eventually opted for a solution as follows:


Using a mobile POS app for sales
Sending sales from each instance of the app into a central drupal installation running maceij’s version of commerce_marketplace
This way,sales can be separated and/or aggregated by location, POS, etc.