Most probably someone reports post from your profile. Doesn't matter if the post made back three years or more either post merited or not, if the moderators think that's spam means they would delete your posts. I believe you have gotten ban due to a massive report. Just getting merit on the post actually doesn't prove that post is a quality post. Because merit would manipulate or send by mistakes as well. Nothing going to change by arguments, just behaves yourself for the future and try to contribute to the forum.
Most of you guys who comment under this title are not sincere. You're commenting just for comment.
Just use report button for them.
Thank you for making the most descriptive and correct comment so far. I am trying to explain this too. Someone is constantly complaining about my account and I don't think my posts are being reviewed. Upon complaint, my direct posts are deleted and my account is ban. As you said, I will report unnecessary messages from now on.