Hello Asad,
If you're looking to get the placeholder type you could either use CampaignExtensionSetting by querying for the
extensionType attribute or use the FeedMappingService and query for the
placeHolderType attribute.
If your concern is different, could you please enable logging and share us the complete SOAP request and response logs along with the client Customer Id, so I can take a look? You can reply back via Reply privately to author option.
Thanks,
Bharani, AdWords API Team