A few days ago I received an email from Customs and Border Protection. I stated that I got on September 25, 2012 a B1 / B2 visa, expiring on September 24, 2022.
 I booked my trip from November 20, 2017 to February 20, 2018 with final destination to Hawaii.

A few hours before the departure date (November 19, 2017) I tried to check in online on the American Airlines website, for me and my girlfriend. Her check-in went through, but not mine. They asked me to fill the Visa Waiver Program, even though I had a visa for 6 months.

I tried to call somebody in Italy to have some explanation, but because it was Sunday, I didn’t get any answer. I was very worried so I went online and I filled the form of for the Visa Waiver Program.

When I did the check-in at the airport, I asked and they didn’t see any problem about my B1/B2 visa. They told the maybe it was some technical problem.

Only last night when I got that email I realized that my passport was stamped with the 90 days ESTA visa, and not for my girlfriend. Maybe someone can help me to understand. Are airlines allowed and forced to use the ESTA if I still have a B1/ B2 visa?

What are the consequences, if next year I wish fly back to the USA? Can I use my B1/B2 instead of the ESTA (which is valid for 2 years)?

I will leave the USA on time, before the visa waiver expires. Please let me understand what I need to do.