The idea of giving spammers a second chance seems truly bizarre to me. Have you ever un-blocked an email address that you previously blacklisted for spamming you? Do you think recipients of spam from this company want to give them a second chance?
I'm not necessarily saying the people behind this should be completely blacklisted from the entire industry, but when a company earns a place on my block list for behavior like that, it's permanent. They need to start over with a different business model. Failure of the company is a reasonable and fair consequence for such scandalous behavior, especially for a company at such an early stage.