Is the office entitled to demand the full commission despite no prior agreement on a price or condition for the commission, after the villa owner's number was obtained from the office, which was unaware of its existence?

When a brokerage office places a sign on a property with its phone number, and then provides the property owner's number to a buyer, this is a form of brokerage. The office is entitled to a customary fee for this service if a specific fee has not been agreed upon, according to the common practice of brokerage offices in estimating the fee for providing the property owner's number.