This company has poor communication over the phone...

This company has poor communication over the phone (very rude to women they treat us like we don't know anything about a car) and will refuse to pay for an engine when I paid for the most expensive warranty they had so I have EVERYTHING covered. My motor blew a rod after an oil change of 3,000 miles and told me due to me neglecting my car they will not fix this. I have 3 mechanics tell me this was in no way my fault and that my warranty should 100% be covering this. I sat on the phone with a customer representative and, he told me to go back to my car's manual and it will tell me how I neglected my car. I went over the whole manual and it said at 3,750 I should get an oil change. I was still a few 100 miles before I needed one and, now that I stated this was from my car user manual they refuse to talk to me.