It has occurred to me, that if you are writing from the USA, Canada or South America, a lack of reply OR 'Not Found' notification from a Comune
might be caused by the following...
Let us suppose that your request involves an 'event' (birth, death, marriage etc.) that occurred on the
11th March 1901.
You send off your request to 'X Comune' for a Birth Certificate for Great Grandfather for this event that you KNOW took place then as all his other documents give that date. So you tell them that his d.o.b. is
3.11.1901. (American date system)
So the clerk 'could' be searching in their registers/archives
between 1st and (maybe) the 30th of NOVEMBER 1901 .
It therefore follows that if the event DAY you are seeking falls between the 1st and the 12th, of any given month, then an Italian clerk could easily misunderstand and be looking in registers
up to eleven months away from the actual date, and of course that will result in a Not Found (Non Trovato).
So safety would dictate that when writing for documents write the date as either
11 March 1901 OR (in the Italian manner as) 11.3.1901