Jessica,
  First this is a common problem with Ancestry or MyHeritage, if you have a public tree.  Secondly, unless your family was ultra-wealthy or famous, any genealogical information that is out there is NOT the cause of identity theft.  Someone would have had to target your family and researched them to get this data to use for identity theft.  Identity theft is based on big breaches of information from hacking online records.  Those records contain Current Addresses, phone numbers, names, credit card numbers and social security numbers.  It is much easier to buy this information from the dark web at pennies per person than to spend hours chasing down the descendants and ancestors of your family or mine.
--
Sarah L Meyer
Georgetown TX
ANK(I)ER, BIGOS, KARMELEK, PERLSTADT, STOKFISZ, SZPIL(T)BAUM, Poland
BIRGARDOVSKY, EDELBERG, HITE (CHAIT), PERCHIK Russia (southern Ukraine) and some Latvia or Lithuania
https://www.sarahsgenies.com