Confused about tracking numbers

[Seikoman59]

I recently printed a postage label through PayPal for an item I sold on eBay. I selected to use Royal Mail International Standard. When I selected "confirm and pay", I was provided with a tracking number, leading me to assume that the shipment would be tracked. The buyer has sent me an email complaining that the tracking number I provided is not working . Confusingly, a bit of reading about this revealed that RM International Standard is a non-tracked service. Why, then, was I provided with a tracking number?

Thanks for your help.

[Seikoman59]

I realised I have just posted in the US forums. My question is about a shipment from the UK. Does this need to be moved to the UK section? I apologise for any inconvenience caused.

[sharpiemarker · Accepted solution]

It is a customs label number. All intl shipments have one in general.  If shipping method used includes tracking, the same customs label number is used as the tracking number.

[Seikoman59]

Thank you for helping

[RonPratt]

Where do I put the tracking number of a returned item