Grandmother Stuck Paying $14,000 Because of Building Issue

Essentially when my grandmother (64) and I (18) lived in a rental home in location: New York. During that time the electricity bill skyrocketed. We had the top half of the home while the neighbors had the downstairs. Long story short we believe the landlord was using the electricity for the downstairs home/construction. She asked the company to send someone to check and they refused saying the landlord must give permission.

The bill is in my grandmothers name and now she is stuck paying $14,000. The other adults in the household have looked the other way refusing to help pay or get answers. It is unfair she is stuck paying such a large sum and I am just an intern and a current college student, I do not have nearly enough to assist her. Is this legal? Is there anything we can do?

She moved to New Jersey after the landlord essentially kicked us out to build an apartment complex over the land and I remain in New York with some family as I complete my studies.