Charge for hulu after cancelling plan?

I moved my phone number to another carrier in December, then I received a final bill in January (covering the period of Dec 9 - Jan 8). The final bill was for $7.80, with $3 of that being for my plan and $4.79 being for Hulu (+taxes). The bill said the increase for Hulu was $4.79, so it's not a charge I was paying before. Does anyone know why I got charged for Hulu after cancelling, when I was never charged for it before?