If you have a converter, you should not need any house battery if you have shore power. So while waiting for new batteries, get that converter working. (Could be several reasons it is not working.) That should get the levellers working too.
If you have an inverter/charger then with dead house batteries you have no 12v to the inverter/ charger, so the charger part won't work to recharge the batteries. New batteries will solve that, or just jump those batteries and get the charger part enabled to recharge the dead batts. (if they are worth recharging)
If no 12v to the house from running the engine, that is another thing that needs fixing while waiting for the new batteries.
It may be that your levellers have their own fuse or breaker that is "open" and that is the real problem.
