Main sewer line runs down middle of drive that is supposedly shared but I do all upkeep and use it. Owner rents out that house. I did Main replacement

Main line runs down middle of drive and found out when doing replacement it is connected to house next door. My basement was flooding with sewer backup and that house was vacant. Driveway is supposedly shared? I had line replaced and now want to concrete the driveway. Owner of house next door lives out of state and rents the house out. He won't help pay to fix driveway and has not offered to give any money for the main replacement. What are my options? The city told my contractor he was not allowed to disconnect the pipe from the neighbors.