Retirement tax questions

Similar for me, my 2a is blank, the 2b is not checked, and it was a total distribution because it was from a death benefit, and that is blank too.  Now I know it's improperly prepared but my taxes happen to be due today because I owe.  Turbo tax says 2 a must have a value, even if it is zero.  If I put zero, they owe me a ton, which I know is wrong.  So I'm stuck and I don't know what to enter