I paid 50 dollars/month for many years, and didn’t change my plan to more expensive one, yet this February I received a 5$ increase not including tax. What is it? Can someone please explain.

What does expires mean? I didn’t have any tab plans or other time-limited contracts.
In addition to that, my plan now doesn’t show any relevant info in dropdown:

I compared Jan and Feb bill and they differ only in 50/55 number, that’s it.
How to revert it back?
Thanks.