I bought several Malwarebytes CDs with lifetime license keys many years ago from Newegg.com. After use of one on a PC for 2 years, suddenly it appears as "blacklisted." NOWHERE on this company's site do they address the blacklisted issue; only "too many PCs" ... I've never used it on but one PC at a time, never registered them with Malwarebytes, always deactivated on old PC and reactivated on new PC without issue. Until now. I've opened a support ticket, waited 3 days for an automated response that said "send proof of purchase" that I don't have, and replied to the email with a screenshot of the error message and my key info and a scan of one of the remaining copies I have that's never been installed.
I agree with all who have blamed the corporate greed of Malwarebytes (who used to be a dedicated group of security experts and coders) to unload this kind of crap with no warning and no chance to explain what to do to avoid such issues. Seems the original creators have made their millions and have moved on to leave legitimate purchasers of this software product to twist in the wind.