. >> erica stewart teaches 4th grade math in redwood city, one of four teachers to win the 2016 fishman prize from teacher advocacy nonprofit tntp. the award recognizes the most effective teachers working in high-need public schools. you have to love what you're doing. >> she wins $25,000 and a six week residency this summer. congratulationss. >> yes. >> when you buy a car, or appliance, you might buy the extended contract. >> did you know the law allows you to cancel those policies? >> i wanted a bigger car. >> it meant she can cancel the contract for the older car and get cash back. >> i called and he said yes. you are entitled to a refund. >> joan paid $2880 for this six-year service contract. and she cancelled it. customers are entitled to a refund for the unused portion. >> i was told send us the bill of sale and cancellation form. >> nissan infinity agreed to refund her $2500 for the unused portion. >> and i waited for a while. >> reporter: she called nissan. nissan said the dealership had been sold. >> the new company is not honoring refunds. >> joan explained new owners were sti

. >> erica stewart teaches 4th grade math in redwood city, one of four teachers to win the 2016 fishmans the most effective teachers working in high-need public schools. you have to love what you're doing. >> she wins $25,000 and a six week residency this summer. congratulationss. >> yes. >> when you buy a car, or appliance, you might buy the extended contract. >> did you know the law allows you to cancel those >> i wanted a bigger car. >> it meant she can cancel the contract for the older car and get cash back. >> i called and he said yes. you are entitled to a refund. >> joan paid $2880 for this six-year service contract. and she cancelled it. customers are entitled to a refund for the unused portion. >> i was told send us the bill of sale and cancellation form. >> nissan infinity agreed to refund her $2500 for the unused portion. >> and i waited for a while. >> reporter: she called nissan. nissan said the dealership had been sold. >> the new company is not honoring refunds. >> joan explained new owners were still responsible. nissan said it had no paper work. >> they lost the applica

we you snuck into erica stewart's fourth grade class in redwood city along with her parents to be there to announce that you won this year! >> reporter: ms. stewart is wufrn of four teachers nationwide to win the 2016 teacher advocacy nonprofit tntp. the award recognizes the nation's most effective teachers worg, with high-need public schools. she was nominated by her principal kyle schafer. >> everybody give her one clap, two claps, ten claps. when you sit in ms. stewart's class, it really is a magical place. >> reporter: the fourth grade math teacher wins $25,000 and a six-week residency this summer where she and the three other prize winners will meet with education leaders across the country and write essays about their insights in the classroom. need proof ms. stewart is a top teacher? listen to her exude student. >> she explains well and i get good grades and then i feel good about myself. >> we have fun when we're working hard. >> reporter: working hard is a theme in ms. stewart's classroom. and what she credits for her and her students' success. >> raefl, really hard work. and y