Park car in Lisbon parking lot, it's cash only, so take out minimum cash at ATM possible which is €10 but parking only accepts €5 or coins, I ask why...

park car in Lisbon parking lot, it's cash only, so take out minimum cash at ATM possible which is €10 but parking only accepts €5 or coins, I ask why, and I get scolded for not reading the paper on the machine, but I did read the machine, I just ask "why" but he can't answer except for scolding me, then try ask for change outsidd but of course no shop wants to give me €5 euro change so I have to buy water somewhere for €1.70