Hi Patrick,
Thank you for reaching out.
Instead of using the CampaignFeedService, you can use the
FeedService.get() as this service will be able to get all feeds associated in your account. However, it is also not possible to get feeds associated to the Merchant Center. The feeds supported are only the
feeds created by user and feeds that are system generated by AdWords.
Let me know if this answers your concern.
Regards,
Dannison
Google Ads API Team

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