I recently purchased a triplex in Wisconsin that is heated by propane. The tanks are rented from a local company. Recently, we had a tenant call and inform us his unit had no heat. We asked if he checked the tank and he said yes and the gauge read 40%. So, we called a HVAC specialist who arrived and informed us there was no propane in the tank and the gauge was wrong. We called the propane company and told them and they filled the tank the next day and charged an emergency service fee. The gauge still read 40%. We did not agree with the emergency service charge so we went to the office and explained that it would not have happened if the gauge was correct. The following day they checked the gauges and replaced them. That evening, the tenant called and stated the gauge is reading 80% now but there was a noticeable leak. We again called the company who sent someone out and confirmed it was leaking. The next day they replaced the tank and called stating we would be billed for additional propane which was added to the tank after the replacement and they would not take the emergency service fee off. 

So, my question is: Am I responsible for the charges even though they are a result of their tanks working improperly?

Any advice would be appreciated.