Tracking myHermes ParcelShop?

I dropped off a return at a myHermes ParcelShop on Tuesday. On the receipt it has a 8 digit code beginning with P, then 7 numbers. However when I type this in to track it won't work.

On the parcel I dropped off there was also a 14 digit number, however this won't work for tracking either.

I was wondering if anyone knew how to track the parcel, since both of the codes I have don't work?

Thanks