Priceline.com review: Best price guarantee

I checked Priceline for a car on the 6th of November and found a midsized car for 41 dollars a day, on the 8th when I had confirmed my travel plans I went back to find the price had gone up to 59.11I assumed the price increase was due to the upcoming holidays. On the 12th of November I checked back and the same car for the same dates through the same company was again 41 dollars. In the mean time I had Been issued an e-mail stating I could sign up to be a VIP member and how wonderful the benefits were so I signed up. I tried to submit a claim as instructed and was unsuccessful when I called customer service they said I could not receive a reimbursement because I was not a VIP member. after looking at my trip itinerary I noticed it said "This trip is eligible for our Best Pric Guarantee. As a VIP member, if you find a better price for this trip we'll refund the difference. I know I was not a VIP member at the time I booked my trip but this is the same car for the same dates through the same company! I feel I am entitled to a reimbursement for this reason. I have been diagnosed with terminal cancer and need to save every penny I can, so this is very important to me. I hope whoever receives this has some sort of decency, this just is not good business!