Q1 visa - Request for evidence - form 1-693


I'm in the states on a Q1 visa.

My spouse and I have just received a Request for Evidence.

The letter says that the form I-693 was not submitted.

We are 100% sure that we have submitted it in a sealed envelope.

I double checked our copy and everything is filled out correctly and signed.

There is only one little mistake in the first page of the form I-693: I wrote 26/04/2016 in the date field, next to my signature, instead of 04/26/2016 (in fact it's specified that it needs to be written in the mm/dd/yyyy form). The Civil Surgeon signed it on 04/29/2016 (date of completion) so it should be understood that what I meant was April 26th.

Can that little mistake be the reason why they sent me the Request for evidence?

What should I do?

Thanks in advance