2004 x3 Back window explosed while driving

What is your question?

I was driving I heard a loud pop like gun shot nothing hit my car the window just exploded. Dealer is trying to charge me 1750!!!! I refuse to pay because I just had window replaced year and half ago because deforst would work, windshied wiper fluid, and radio. In addition 2 weeks ago now front windlield wiper didnt work and they said $1600 to repair that because they have to go into the floor boards. Anyone else with this problem?