Auto Insurance Claims: Car Rental reimbursment, own insurance, car coverage

Question
In July 2009, I was rear-ended while at a traffic light (NY State). I went through my own insurance company to have my car fixed.  I have rental car coverage of 80%/20% with a max of $500.  I had to get a rental car for 29 days.  The accident was 100% fault of the other driver, his insurance has paid my insurance their portion of the rental car but has told me they will not pay more than 19 days of rental car because they believe based on the estimate that  it took the body shop too long to fix my car.  They say they are also only allowing $22/a day.  Are they responsible for paying my 20% out of pocket for the entire time I was in need of a rental car?  I was never told that only 19 days would be covered until 2 months after the accident.

Answer
Send a letter to the liability carrier for the other party and tell them that you will take legal action against their policyholder in the absence of a settlement for 100% of your costs. Send a copy of the letter to the at-fault party who hit your car. You had no control over the time it took to repair your car and would not have been in a position to rent one had their insured not hit your car.