i erased my 2nd gen ipod touch, can it be restored, apple shop are saying no , some parts can not be downloaded. is this correct

Sorry new to all this.
I was re-selling my ipod touch 2nd generation so i erased all contents and setting ... was this correct ?
The new owner is telling me she cant get it to work. she has taken it into the apple store and they have told her that parts that were erased ca no longer be downloaded.
Is this correct ?
Have i been an idiot ? lol