QR code

[george98-uk]

I have sold 5 items to a buyer and had 5 QR codes (each the same). I parcelled up 5 items separately but only 3 of the QR codes were recognised at the post office counter. What could be the reason 

[style_wise]

eBay says:

"Postage will automatically be combined if your buyer purchases multiple items from you and completes checkout in one transaction. If you're sending multiple items from one order, all items will need to fit in one package which meets the Simple Delivery package limits."

Did you pack all 5 separately because they exceeded parcel limits (e.g. Royal Mail Large Letter over 1kg, or RM Small Parcel over 2kg)?