Business ProfileforCashway Oil Co

i ordered 100 gallons of oil from cashway oil which was delivered. apparently there was another delivery of 100 gallons the next day. i received a bill for 250$ in the mail about 3 months later. when i called cashway they told me there had been a glitch in their system and they delivered the second 100 gallons by accident. they told me i could either pay for those 100 gallons or they could come take it out of my tank. by that time i did not even have 100 gallons for them to take and i did not feel i should have to pay them for their mistake. 2 days ago i recieved a certified letter in the mail demanding payment of 350+ dollars or they were going to take me to court and put this against my credit score. i called them again and asked why i should have to pay for their mistake. they told me that either i pay them 200$ or they are taking me to court and thats all there is to it. i was reading reviews about this company and saw that this has happened to a lot of other people and have been thinking that this is what they are doing to their customers so they can keep their oil prices below competition!!!!! their oil prices are way below competing oil companies. my family has used this company my entire life and i cant even believe how rude they have been and how they can DEMAND payment for their company/driver or whoevers mistake. times are tough right now, im a single mother and i have no extra money to spare to pay for their mess up. please help!