Does the estate of a dead cosigner have to pay for the loan if the primary is in default?

the primary obtain insurane online, listing the bank as the lien holder, the policy was also faxed to the bank, the car was then totaled in an accident, now the insurance company and the bank will not cover it because they state the policy did not have full coverage. how can the insurance co. & the bank not notice that the policy did not have the correct coverage needed by law/ - Is this your question? Add additional information