House terrace and compound wall issue

Dear sir, We had purchased a land in a residential layout in the year 2005 measuring 30'x40' and constructed the house [only ground floor] without pillars and beams. Ours in a 2nd site from the main road and in between our site and first site, a high tension electrical wire was passing. Hence in the layout plan, the owner had given a 5 feet gap due to high tension electrical wire was passing. Since, 5 feet unused space was there in the layout plan, we had extended our house terrace and compound wall by 2 feet. Now after 14 years, they have shifted the high tension electrical wire to road side. The owner now is building a godown for renting to fabrication work. He is threatening us that, he will demolish the terrace & compound wall and window sarja. We requested him not to do so since if we demolish, it will damage our house since there is no pillar and beam support. Instead we will pay for the extra space consumed or we will demolish the same, when we are constructing the house with the beam and pillar. He is not at all agreeing. Pl guide us how to solve this issue.