*EDITED IN RESPONSE TO DEVELOPER'S REPLY BELOW*
Our errors are occurring due to our online store being integrated multiple times on C&D, as opposed to a single integration that's creating duplicate orders. This issue is caused because every time we launch C&D - regardless of wether it's from within Shopify's dashboard, or visiting the app URL link directly (as recommended by the developer themselves in their reply below) it still creates multiple integrations - so even if we access C&D via a direct URL, it still continues to create multiple integrations and subsequently, cloned orders. For us, this recommended workaround is no longer working consistently and needs urgently addressing for all users.
*ORIGINAL REVIEW*
I honestly cannot comprehend how bad this app is, if you want something to assist the derailment of your online business, use this app.
As others have said, the synchronisation is terrible, it constantly re integrates your online store so if you have, let's say, 10 new orders for example, it will show up in the Click and Drop app that you have 30 new orders, and then the order numbers will not sync up to the back end of your shopify. Every time we open this app, it reintegrates as a new store connection every time, causing endless clones of multiple orders that become incredibly difficult to keep track of.
It used to work not too bad. I remember seeing a review on here a while back where someone said to never to launch the app from your shopify dashboard, but instead just bookmark the URL for the app's home page, and visit it directly from a new tab to avoid the repeating integration issue. This hack was working well for us for a while, up until recently, whereas now it seems that regardless of wether you access the Click and Drop app via shopify dashboard, or by visiting the URL directly, it just doesn't sync up correctly to your store and/or pulls in an absurd amount of duplicates.
Surely this must be one of the biggest and most used services for small UK online businesses, and this is the state of the app and it's functionality? The fact that the same complaints have been echoed on other reviews for so long shows RM's total lack of support or motivation to actually fix these errors too. Diabolical. Please hire a new, competent developer team that actually does their job.