Actually, Activision sold you Black Ops 2. It's not a Sony game. I'm sure that Sony is sick of you blaming them. The fact of the matter is that probably no one can fix the lag in the game. It isn't lagging for everyone. That means that the netcode isn't at fault, and neither are the servers (which are also run by Activision, FYI). It's not a hardware problem either, or a System software problem, so there is nothing that Sony can do. The problem is with your network connection, which does not have a low enough latency. Of course your ISP says that there is no problem. The truth is that there is no problem that they can fix. ISP networks don't have a guaranteed latency, and there is no guarantee that the latency of any broadband service that you choose to buy will be low enough to play games like Black Ops 2. Contrary to popular belief, the game doesn't work well on just any Internet service. Network latency is the result of many factors in the network, and there is nothing that your ISP can cheaply or easily do to make its network delivery packets faster between your PS3 and the game servers. Latency is largely unrelated to bandwidth, so signing up for faster Internet service usually doesn't improve latency, and therefore doesn't solve lag issues. The only thing that you can do is to try a different Internet service, e.g. DSL or FiOS instead of cable modem, etc.
Who you arbitrarily choose to hold responsible is irrelevant, and important only to you. Complaining to a party that has nothing to do with your problem is a waste of your time, and theirs.