This is in the playbook of the RCC - ignore letters, even if asking questions that demand a response.

The hierarchy won't even acknowledge reception of letter which is a pro forma immediate turnaround of any decent business, let alone an institution that proports to be a moral one!? A financial donation will receive acknowledgement though!
Recently, I wrote pope's WDC delegate, archbishop Pierre, to respond to issue in my home diocese of Manchester, NH where the local bishop allows "a priest in good standing" to cater to a cult, The Slaves of the Immaculate Heart" or some such nonsense. Even though diocese acknowledges they are not recognized by RCC, he allows them a priest to satisfy their peculiar worship preference. The group is identified as a hate group by the Southern Poverty Law Center.
No response or acknowledgement of letter to Pierre.  I had to call embassy where receptionist finally said it did indeed go through.  No response from Pierre, though! The RCC way.