I appreciate you for adding clarification about your concern with downloading QuickBooks POS to your tablet and for performing some steps to achieve this, igedesign. Let me route you to the right support team to assist you further on this matter.
I recommend contacting the Shopify Support Team. This support is the best resource for such inquiries, as they can request account information. They can verify further why you're unable to download the QuickBooks POS on the tablet and resolve it so you can access the old client history.
In case you need steps on how you can resolve unexpected errors you might encounter when opening your company file in QuickBooks POS, you can read this article: Errors when opening your company file in Point of Sale.
I'll make sure to circle back and provide the necessary support if you have further questions or need assistance handling your data with POS. Take care always, igedesign.
