I imagine they closed the inactive account because it costs an increasing amount of money to send emails to email subscribers. Rather than eat the costs of all the thousands (or more) inactive email addresses being delivered to, and on a regular basis, why not save some money by truncating the list of subs, down to only the active users? From a business perspective, it makes sense, and I'd do the same if I were them. I can only imagine how many email addresses CPA companies have in their databases.
I just pulled this data from Aweber, which is one of the more popular email autoresponder suites:
So again, I don't know what the number of email accounts is, with regards to Crakrevenue or any of the other popular CPA companies, but it can get very costly, very quickly. Not to mention all the trolls that create email accounts to simply join just to join. Then there are those that opt into the mailing list because they want to spin the emails to send out to the subs of their own lists, and then the other people using those emails for other types of affiliate marketing ventures, etc. So every so often, why not trim your lists of inactives? It only makes sense.