We've had the technology for some basic battlefield-robotics for a while, and yet things as simple as unarmed camera-drones still aren't commonplace. It's not about them being vulnerable to hacking, or ethical concerns...
It's all about the about money.
Consider, for a moment, that the average Private in the US Army makes less than 20,000 USD per year. Even a Staff Sergeant makes less than 30,000 USD in annual salary. That means that paying the yearly salary of an entire fireteam (Four people, usually several privates with at most one Junior NCO) costs around 90,000 USD - Less than a mid-to-high-end luxury car.
For comparisons sake, a single Javelin missile and command/targeting unit runs nearly 200,000 USD. A single shot for a vaguely high-tech weapon costs as much as 10 men. I don't have any hard figures on infantry-scale combat robotics, but I can only assume they'll easily reach into the millions of dollars.
Unfortunately, life is cheap.
You might call it dystopian, but our world is already in a place where it's cheaper to pay people to die than it is to build robots and save lives. Now, I assume your evil crime-lord/ mad scientist has the funding to afford robot soldiers. Let's also assume that they're tougher, faster, more heavily armed and more psychically-resistant than your average non-hero. They can take a headshot and keep fighting, and they never miss (Unless they're aiming at protagonists.) Perfect fighting force for every situation, right?
But.... For the price of just one of those robots you could probably pay several dozen if not hundred undesirables to do your bidding. The more poor and destitute they are, the more cannon-fodder you can afford to simply throw at the problem. As an added benefit, if they die you no longer have to pay their wages, whereas your robots would require an astronomical repair and maintenance budget.
As Nex Terren pointed out, these robots may have super-human abilities. However, since we're in a world of cybernetically-augmented psychics. By our standards, everyone is a superhuman. Therefore, I don't think it's a guaranteed win for the robots.
An important question to ask is what these robots were meant to do. Perhaps Nex Terren is right, and the battlefields of the future will be completely robotic. In that case, our big boss might have black-market military surplus, in which case the robots are built to fight... Well, other robots. While it's gruesome to think of what an anti-armor weapon would do to a human, a non-armor-piercing light machine gun is simply a better weapon to use against people. If this is the case, the tactics could be as simple as 'Trick them into firing, and attack while they're reloading.'
Or maybe the robots are stolen riot-control droids, or hacked construction units with a very.... Liberal definition of what requires sawing and welding. Maybe they're custom built sentries that shoot anything without a transponder on-sight. I could speculate robots and countermeasures all day, but it's very hard to come up with tactical level counters to a force you know nothing about.