Yair Hi! If you check your invoice (Profile > Settings > My plan) you can see all costs and why you had to pay. But my guess is that you already did four cash withdrawals this month, and then it's €0,99:
"First four withdrawals per month are free, the five after are €0.99. Thereafter, €2.99 per withdrawal."
More info: https://bunq.com/pricing-sheet