Can Smart Meters Overcharge?

We recently had smart meters installed through Bulb. The electric meter is not talking to the lhd but that’s another matter and not what I’m here for.
I’m pretty sure our smart meter is making our usage level up!
Most mornings when I leave the house it’s showing that we have used about 20p worth of gas, even though we have not had the heating on or used any gas in the kitchen.
Today we reported a gas leak and National Grid came out around lunchtime and turned off the gas supply until we can get the leak looked at.
The smart meter however has continued to rack up gas usage and is now at in front of me reading 97p.
The gas is still turned off.
What’s going on! Anyone?
I’m not sure I trust these meters at all.

The 20p is the standing charge. It’s added at midnight every night.

The rest does sound like there’s something wrong if the gas is turned off at the main incoming valve.

If it is just the 20p as Hooloovoo suggests that will be the standing charge, however did they turn the gas off based on the 20p or did they hook up a pressure meter to see if in fact it is leaking. I accept you now say it is 97p which does point to leakage but as you state that could be a meter fault other than a gas leak.