Munir Ok then please contact both bunq's Private Support as well as the Italian bank about this. bunq Support should be able to look into your payment once more and make sure everything went well. With the payment information, the Italian bank should then be able to check if they ever received such a payment and what happened to it. If you're not the account holder of the Italian bank account, please forward all the information about the payment to the account holder and ask them to contact their bank.
You can reach Private Support in the bunq app by going to the Profile tab > Menu 🌈 > Get Private Support.