Hi @June2
Thank you for your post.
There are a few things which could have affected why the bill could have increased, while your usage appears to be unchanged.
If you were receiving estimated bills before it got changed to a smart meter, then a reading would have been obtained as they changed the meter over causing a catch up of usage.
I'm more than happy to look into this for you. I'm going to send you a Private Message to get further information.
Thanks, Chris