00800 00 382284
This is Ducati's toll free number you can call from anywhere in the world. I have just spoke with them and told them of my issues which are the same as yours (won't start after it's hot).
He has advised me to get back in touch with the dealer and tell them you need to take the bike back to them and try and replicate the issue whilst they're watching. Then they need to take the bike and see if they can locate the issue. If they can't, they have internal channels which they need to ask for assistance from Ducati in resolving it.
He also said that if they're being reluctant to do this, they can intervene on your behalf (whatever that means).