It's never a good thing to feel unappreciated or underpaid. If your employer refuses to give you what you consider a fair wage, start looking elsewhere. Many employers tend to operate on inertia: Unless you're about to leave, it's easier to just ignore your problems. It's up to you to spur them into action, which it sounds like you've been doing to varying degrees, but if they still refuse to move, you have to kick it up a notch. Find a better offer from another company. If your current company truly values you, they will try to keep you on board. If not, you have a better offer anyway and will likely be valued more at the new place.