A politician can do very little with your grievances, unless they are very common, in which case, the more people write to them about their problem, the more likely they are to push or support an executive or legislative remedy.
In certain circumstances, where the situation is sympathetic and the remedy is just flexing political power, like a process being held up in red tape, causing something bad to happen to you, I have found politicians very helpful. They can only moderately affect the law, but they do have “pull”, and most are amenable to the idea of using their soft power to help a constituent.