The staff don't have to apologize for this. You let the alarm bells ring by sending in a message or post a couple of times. Nobody said you are a spammer. You only activated the spam alarm. They have to use it otherwise people could post hundreds of spamming messages before the staff notices this.
What's wrong in posting a couple of times?
Chess.com should have absolutely no problem even if I want to post 100 news in my group within a minute.
Nothing is wrong but it triggers the spam alarm. Because it looks like spam.So don't be suprized when you do it and the spam alarm will react.
I neither sent an invitation nor flame through PM. There was simply no reason to close the account. The software mistook it for spam - and that's the fact.
On the other hand chess.com's response shows no regret - if anything, it insinuates I must have done something wrong for my account to be closed (the first para). Well, I did nothing of that sort.
As for kohai, she is the most helpful and fair minded person I have come across on chess.com. In fact it is unfair that she has to face upset members like me all the time, for the shoddy work of someone else.