Your meter only causes disputes; I would mentally erase it.
Since we also had a few extra weeks attached this year, the risk is very high that he consumed more again and then we pay again?
Do you have the neighbor's meter reading from the time you disconnected yourselves from the neighbor? If not, then urgently catch up on that now.
You will probably be living there longer. Your consumption at the neighbor’s place can be determined statistically over the neighbor’s electricity consumption – but not today.
You should go into pre-financing. With money in hand, you can surely agree to review the neighbor’s normal consumption again in 1-2 years and, until then, obtain his meter readings at certain intervals. Then everything will resolve itself.
We also can’t just pay 5-8 times the electricity that, according to my research, others pay. Even though we still have many costs ahead, we have to stick to our calculation somewhere.
And for what reason could it have been our fault? Our meters will hardly both run incorrectly, especially since the construction power meter has already been checked.
These are not even remotely his problems from the neighbor’s point of view.
If you accuse the neighbor of deliberate enrichment at your expense, then don’t pay and settle it in a dispute.
Otherwise, I would come to an agreement with him. He is not responsible for your meter reading, whether it is right or wrong.