Inverter not recognising 2 batteries

Support not responding to my requests for help (first request Jan 10th) so I thought I would ask on this forum.
Everything working OK until the New year.
App says I'm not exporting power but energy supplier says I am and paying for it.
App and webpage both don't recognise any batteries, even though I have two that were working perfectly OK.
Powered down and then up (whole system) a number of times but no change.
System in a garage so not exposed to the extreme cold weather.
Dongle on ok and constant colour
Invertor lights on.

Any help and suggestions on what might be wrong would be appreciated.

EatonPaul What sort of system do you have? Hybrid, AC ? (I assume not AIO since you mention two batteries.

If you have an Android device, have you tried the 3rd-party inverter app - https://givenergymonitor.wixsite.com/tutorials ? That would give an independent view on the status of your system. An alternative is the multi-platform "bbc basic" app - https://community.givenergy.cloud/d/5051-bbc-basic-inverter-app-significant-update