Try re-sending what you already did along with the laws showing that what you provided is the legal divorce document for your country.
Also, provide a copy of this from the Dept of State website>
https://travel.state.gov/content/visas/en/fees/reciprocity-by-country/BR.html
Divorce certificates are available as an amendment that is annotated on the previous marriage certificate.
Your tourist visa it's cancelled in the minute u cross the USA customs with the K1 visa.
The officer in Miami or any airport you entry will stamp your B1/B2 visa with "Cancelled by procedures" something like that...this means you didn't do anything wrong for having it cancelled it just intern procedures.
I know this because my friend who just got married with an american she told me that. Which means that if something bad happens and lets say u dont get married in 90 days ur K1 expires u will be out of status in USA and yes if u leave USA before the 90 days expires and decided to come to USA later as a tourist you will have to get another tourist visa. Fill the form.. pay the fee..all over again.
If you think about it does makes sense, because if u applied for a K1 visa u will later become a citizen and not a tourist after marriage.