Hi...Does anyone know the minimum

20 eur

Well I could not spot it in this link here, perhaps Ugo canpoint out the exact place it tells you?

from all postamat Attention , some times , the bancoPosta trasparency documents are not updated :) however  ,  try  not cost anything  ...

It will be 20 euros, as very few cash machines now have 10 euro notes.   I suggest you put your card in, ask for 20 euros and see if it accepts your request.