I met a girl from Canada. She visited for 2 weeks in July 2014. She went home for a month. She came back and stayed for 5 months. Then again returned to Canada in December 2014 and returned January 3rd, 2015.

She stayed until August 2017. When a family member got deathly sick, she left to say her goodbyes. She's still in Canada. We checked on the US arrival and departure records. It only shows her arrivals to the US and not her departures. She claims the Canada border agents never scanned her passport once.

Since her passport was not scanned, is she banned? If so, would I be able to marry her in Canada and still petition her to the States?