Chainsaws

I was useing my chainsaw and it seized up. I removed the spark plug sprayed wd40 to loosen it up. Now it has no compression. Took it in for service. They said it was not covered under warrenty. They said I used the wrong mix of fuel and the cylinder was scored and overheated. I used the product that came with the saw. They said it is not covered under warrenty. Now what do I do with it. It is aprox one year old.