Carta or Permesso Refunds only.
There has been lots of people that have paid using the wrong payment slip in the Post Office, the only way to get a refund is by contacting the Ministry of Interior and requesting a refund, the Questura or Poste Italiane will not process refunds, the money went to the Ministry of Interior.
You need to write to
Ministero dell’Economia e delle Finanze
Dipartimento del Tesoro
Direzione VI Ufficio IX
Via Salaria, 712
You will need to include your Name and Address, details of how you want to be reimbursed so your IBAN from your bank account. The original of the bollettino you want refunded.
Best to use registered post as you are sending the original.
Now please be aware they may require you to have a €16 tax stamp in this case they will contact you regarding it. It seems hit and miss on whether you need the tax stamp.
Don’t forget to explain why you are asking for a refund, they don’t just refund unless you explain why.
As this is Italy always include a copy of your identity document and codice fiscale.
You can use the following form we created and fill it in and send it, which will make life easier for you. The form allows you to get a refund at the post office as well, so choose which is the best option. Post office refunds tend to be quicker.