AUBURN – An oil company is suing a local law firm, saying it broke its promise to buy oil this winter at last summer’s prices.

Attorneys for Downeast Energy Corp. of Lisbon Falls wrote in a complaint filed last week in Androscoggin County Superior Court that it executed a contract with the law firm Linnell, Choate and Webber on June 25 to supply 4,055 gallons of heating oil at about $4.36 per gallon to the law office on Pleasant Street.

The price of heating oil has dropped unexpectedly since summer, when some people and businesses locked in prices. The statewide average, as of Monday, was $2.28 per gallon, according to the governor’s office.

The lawsuit says the law firm had taken delivery of 1,119 gallons of oil by Nov. 6, about one-quarter of the contracted amount for the season. In a letter to the oil dealer, John Conway wrote that his office expects to pay for that oil and only that oil.

Conway, a lawyer at the firm, wrote in a November letter that he never got signed approval of the agreement from the oil company, so he was canceling the contract. He also wrote that he had hoped the oil company would adjust its prices downward due to lower operational costs, but never got an answer from the oil supplier.

Conway said Wednesday his firm has paid for all of the oil delivered and believes it has met all of its obligations under the agreement with Downeast Energy. The firm expects to file a response denying the allegations made by the oil dealer.

Downeast is suing for breach of contract and is seeking compensation equal to the difference in sale price of the remaining 2,936 gallons set aside for the firm and the higher contracted price. It is asking for other damages and costs.

“We don’t believe we breached anything,” Conway said.

A clerk at Androscoggin County Superior Court said she hadn’t come across any other complaints brought by oil companies against customers alleging they breached purchase agreements.

A state law enacted in 2005 requires Maine oil dealers to buy at least three-quarters of the oil prepaid for by customers or to post a bond or provide a letter of credit for the early sales. That law was passed after a couple of dealers cheated early-paying customers out of their oil.

Some heating oil customers will pay during the summer to lock in a price. Others agree to a fixed price and pay monthly for the amount of oil they anticipate needing for the winter.

Claudette Townsend, regional manager for Dead River Co., said most customers who take advantage of Dead River’s “price protection” programs pay a premium of 25 cents per gallon to cap the amount they will be charged per gallon.

That way, those customers aren’t stuck paying twice the amount of the current market rate, a situation some unhappy homeowners have found themselves in this winter. Had the price of oil gone up since last summer, a cap would have protected customers from paying an even higher price.

There’s always some risk involved when buying heating fuel, Townsend said, especially in this year’s volatile energy market.