Do all AR services allow you to re-sub unsubs?

I currently pay 150 a month to an autoresponder service - the same one many people here use.

I've been spammed from one of their customers for at least 2 years now - I always unsubscribe from this persons list, only to be magically put back on the list a bit after.

The only reason I've never just hit the 'spam' button to make it all go away is because I also use this service - and you can't go a week on this forum without reading a thread about their plummeting delivery rates, Yahoo blacklists, etc.

However, I was just added back to this persons list on Jan 18th, so I figured enough was enough. (this has been going on for 2 years now)

I opened a live chat support with the autoresponder company - they told me that their customers can manually resubscribe someone who has unsubscribe from their lists previously.

When I asked why in the world that would be allowed, I was told that it was in case they had a client unsubscribe by accident.

Am I the only one who finds this a bit strange?

I've unsub'd from this list I don't know how many times...doesn't do any good. I was told I was the ONLY one who has made a formal complaint against this client - therefore they don't seem to think its an issue?

Their only solution at the time was to blacklist me from this persons list so I wouldn't receive any more emails - but that doesn't address the real problem - that they are allowed to add unsubscribed users back to their list (without opt-in confirmation) whenever they want.

I was told yesterday I'd get a reply back from their 'best practices' department, but nothing yet.

Is this a normal thing? I know most of the users here have an account with AR services - when somebody unsubscribes, do you just go put them back on your list and continue to email them?