" That shows that management is manipulative hiring a guy to to a job but then over time they can get job b, c and d as well for free. "
That shows that you let yourself be managed. Managing is all about manipulation, so yes management is manipulative.
If you are hired to build a shed, and by the end you build a mansion, it's because you chose to. I think it's too late for a raise now. Stick to the other suggestions.
Next time, as soon as you are told to do something you were not hired for, then ask for a raise. In the end, they are supposedly paying you what you were hired for, and if you are going to do something else, they should pay for that too.