Care to give more details? Not fair to just name the firm but don't provide further details apart from saying that their service is bad and that they are dishonest.

Are you aware that dishonesty is a professional negligence on the part of the lawyer? He can lose his license to practice if you can't prove your allegation.

Defamation, and libel, to be precise. Slander is defamation by way of spoken words while libel is defamation by way of print.
I think the name can remain. There's nothing wrong. Just as long as he justifies it. We can wait for a reply. Otherwise, I will report it to the mods to delete the post as there would be no further justification to have such a post.
Care to justify that,bro? 

You are aware that your statement is imputing that the Bar is not neutral body as it professes to be and that it is pro-Opposition. That itself is libel. 

DrTay has already posed her query in this thread and I've already advised her.

In fact, one forummer has quoted my advice in that thread itself.