I am a Six Figure Shopify store owner primarily selling Print on Demand Products fullfilled in China.
Thank you for reaching out to our community forums to share the feedback you have about some of the apps you have been using on your store. I understand that you feel that these apps are not fulfilling/processing orders within a reasonable amount of time and you want to know if there is any recourse for you as the merchant affected by this.
I would be asking the same questions were I in your shoes, and I know that finding this information is not very clear cut. I can't speak directly to our policies around our partners and partner created apps, but I can provide you the next steps to ensure your feedback reaches the correct team.
Feedback surrounding apps is handled by an escalated team that only communicates through email. I would recommend emailing our support with the details you have, with as much proof and examples of the situation as you can provide, so that this can be escalated on your behalf. You can reply back to any of your billing emails or you can create a new ticket through our Help Center. To create a new support ticket please follow this link: Shopify Help Center - Contact Support, sign into your store account, search for your issue and use the contact support button at the bottom of the search results to see all our support options.
It may also be worthwhile to review our policy and user agreements for our partners to better understand our expectations of partner/merchant relationships: