The current version of the eBay module does not allow a seller to import items from a pre-existing eBay account. You must first delete all items from the eBay platform, then add them to the PrestaShop catalog and synchronize them through the module.
If you do not wish to do this for any reason (For example: You have a well established eBay shop and are just starting with PrestaShop), 202-ecommerce offers a paid module called “eBay Import.” This module will only work properly in conjunction with the eBay for PrestaShop module if you have installed and configured the eBay Import Module beforehand.
This module was also created by 202-ecommerce (and can be found in the PrestaShop add-ons search), and is quite technical. There is basic support for any common problems with the installation and configuration of this module. 202-ecommerce offers, as a paid service, configuration assistance should it be necessary. After total configuration, this import will automatically create a new PrestaShop item for each listing on your eBay marketplace platform.