Backdated homeowners Insurance Policy?

The homeowners insurance on my home expired and i was unaware. The company admits that they cannot verify they sent me anything to let me know that I had a bill due or that my insurance was unpaid. My mortgage company now tells me 4 months later that they have been adding monthly installments of an $8k per year policy to my mortgage. I have no claims or damage or anything, but im told that if I can get a backdated policy so that i would not have a break in coverage then they would remove the charges. Does anyone have any suggestions?