Farm Bureau review: won't pay claim 1

I've been with Farm Bureau for ten years, my car has been vandalized, Someone had put sand in my gas tank and poured sand straight in my oil fill tube. I have full coverage insurance and yet they are giving me the run around about paying, I've called several times no return calls all week, I get the 'just stepped outside or their on the phone with a client. I feel like I'm doing their foot work. getting police reports, estimates. The adjuster said that sand will not harm my engine, it was just a coincidence. I didn't believed that, the engine was in excellent condition.
I was stranded on Easter day for five hours. I took my car to the shop 3-24-08, and the mechanic said I would need a new engine, clean out the gas tank, blow out the gas lines, and replace the filters. The damage is estimated at about 2200.00 -2400.00.
The insurance adjuster gave me an alternative, they will pay their engineer 1200.00 to take my engine apart to see if sand had damaged it, if it did they would pay if not they won't. OR they would pay the 2300.00 minus my 250.00 deductible and I pay for half of that. It took them almost a month to get to that part. Now I'm waiting for their engineer to become available.
I pay for a rental car, but I can't get one until the engineers report that sand was the reason for the damaged engine.
So in the meantime, I've been walking to work!