Adt Protectron - Out of Business

I signed a contract for three years. Half way into the contract, my battery became low. I called Reliance to ask them to replace it and they said they would be charging me $50 for a new battery. I refused to pay based on the price and the fact I am still under contract with them. What am I payiing $30 a month for + $50 for a new battery? I told them I would not be renewing my contract. The attitude of the supervisor I spoke to refused to provide a battery free of charge - not my fault the battery is low! He didn't seem to care that I was not happy as a customer and didn't offer any other solution other than pay for the battery or it's my problem my house is unprotected.