I am on free tier plan and this month I received a bigger bill than usual. I started to explore and even though instance shows one volume (id1), when i changed region it again shown one volume but different id (id2).

The mumbai volume was created on 2023/10/10. The north virginia volume created on 2024/05/21 which I do not remember creating. This also explains sudden increase in bill.

I detached the Mumbai volume and the instance did not initiate, then I re-attached it and tried to detach Virginia volume but it threw error Unable to detach root volume.

I increased N. Virginia size from 28 to 29 GB to see if it mirrors in Mumbai volume but it did not. Mumbai volume is attached in dev/xvda, N. Virginia volume is attached as /dev/sda1. sda1 means root volume, which makes this very confusing, how it got created just last month? Should I move Mumbai Volume to North Virginia Region like this tutorial says?

I really need to attend cloud fundamentals course but in the mean time can someone please help me understand what is happening?

Is there anyway I can reduce the bill?