It took all my energy to get EDF to install a meter for my flat

There was only one supplying two flats and I needed my ownI bought my flat in 2016 in a building that had been newly converted into two flats. The developer’s solicitor confirmed in writing that each of the flats had its own electricity account. However, when I moved in, I discovered a single meter covers the two properties and the communal areas. I agreed with the other flat owner that we would split the bills until we get separate meters. However, he now says he won’t pay his half