You could simply not use Verizon's email. That's what I do. That way I get better email service and I don't have to worry about changing my email address should I switch from Verizon.
I have to agree with you. I always mark spam as spam, and have forwarded spam to an email address that Verizon provided to catch spam that was being missed. None of this made any difference and spam to my inbox has increased to the point where most days I get more spam than actual email. It's hard to believe that a communications firm like Verizon does such a poor job at spam management when compared to other services like Yahoo where I have an account.