Thanks, GP. Yes that's about what I was expecting, despite ebay telling me it would take a maximum of 15 days. They have no clue 😞

Btw, to my knowledge, I only clicked once on 'get a postage label'. I am always very measured when I go through that process.  So either a glitch, or I somehow managed to do it despite me best efforts. 

Anyway the cancellation process is underway, so hopefully it will eventually be resolved.