First off let me remind or point out one simple thing. The moment you played the game you agreed to the TOS. In that TOS is a clause where it states that the developers-3ARC retain all rights to the game. They reserve the right to modify, change, add, or remove any feature of the game including mp should they ever see reason to do. They do not even have to tell the players why they did this. They make the choices based upon what they feel is best for the game overall and not just by playlist or playstyle.
Futhermore they know they will upset some players with the changes they make at times. They know this and are ok with this. Because they also know they cannot ever keep all players happy all the time. And no they are not going to try to make everyone happy. They try their best to make as many happy as they can, knowing full well that any change they make will always make someone unhappy. You have to break some eggs in order to make a cake ya know.
Petitions to bring back the game mode, will not help you and in fact are not allowed by 3arc on the forums. Nor do they really take them serious because the signatures can be fabricated. It is very easy to manipulate a poll or petition online to have any number of votes or signatures for an action; yet all those votes or signatures may not be valid so becasue of this the petition and poll is generally considered not valid either or acceptable to 3arc for any reason at all.
Making pictures and then passing them around about the game in any negative format, such as showing the game box over a toilet with the words about it being flushed if hcffa is not returned does not help the situation. Infact these sorts of images hurt the attempt of ever starting a conversation with the developers about them ever considering brining the playlist back.
Making threats, that unless they bring it back you will not buy the next game does not help either. You will not bully the developers by such tactics. Your dislike of the removal will be noted and that is as far as it will go. Your threat has no power over them even if you like to think it does.
Making threats about suing them for bait and switch or theft because of the removal will generally get you ingored by the developers. You would not ever win a court case based upon those reasons. they did not bait and switch, nor did they steal anything. Please refer back to the begining of my post and read the first paragraph again.
Making demands for refunds will generally be ignored. agian refer back to the top of this thread for the reason.
Every negative thread made, only hurts your chances, it does not improve your chances at all. The best method would be to try and pm the developers or send them an email stating your desire and reason for the playlist to combe back. Please make sure if you try this, no insults are used, no threats or demans or other negative speech. And make sure you go in to detail and not just say, "Give me it BACK!!!!111!!", for that does not help your problem either.
You can either take what I said and try to gleam the small bit-o-wisdom contained in it and learn from it. Or you can just ignore it and go about your merry path to oblivion, aka being ignored by the developers.