Any Smart Meter electricians?

I had a smart meter fitted two days ago. I am on economy 7. At midnight the smart meter is not switching on my heating & hot water as it should, so I have no heating or hot water. I have had two engineers visit, both say the meter is working perfectly. They can manually turn on the economy 7 circuit and can feel the storage radiator heating up. Their technical support say they can read the meter and is is running and updating perfectly. But there was a fault reported by the meter on the day of installation, this was cleared the next day. The only idea the engineer have is that the error clearance may not have updated on the meter yet and I should wait till midnight to see if it works then. If it does not work tonight they intend to put a classic meter back in tomorrow. As I have difficulty walking a smart meter would be a great help to me.
I need suggestions as to what they could check if the meter does not switch on tonight. Has anyone come across this before?