Some energy tariffs do require you to have smart meters installed, if you don't have them already, in order to get them.
If you had smart meters installed before 2019, they aren't always compatible with different providers, which means if you switch to another supplier, your smart meter could lose some of its 'smart' functionality.
However, all this means is that you'd have to go back to manually providing meter readings to your new supplier. Other 'smart' functions, such as in-home display of energy use, should still work.
If your smart meter isn't working, contact your provider. It may mean they need to upgrade the meter for you. For full info, see our Smart Meters guide.