I've been with Sprint for three years, and have found that they appear to have very little interest in actually helping customers. Granted, there are a few reps that actually do try, and give a very strong effort. But there seems to be a systemic policy/ethic that negates the value of the customer. It's as though they are more interested in the churn, and replacing customers (the half off deal), than supporting and keeping the ones they have.
I've been dealing with poor coverage in my current area the entire three years. I've heard nothing but excuses.
"we're working on it"
"there's an outage that's being repaired"
"upgrades are scheduled"
"no upgrades are scheduled, please be patient with us, as the future is going to be great"
"please bare with us"
Only once did I get what I felt was an honest answer. About a year ago, a senior tech (who clearly knew his stuff) said "it is what it is, there's no improvements coming".
So to answer your question, there are numerous places you can report an outage. But in the end, I think Sprint has a current plan in place that leaves no room for complaints. It's like purchasing cable, only to find half the promised channels aren't working yet, and you can only get 480p half the time. I don't see how Sprint gets away with it.
Still demanding my monthly "please bare with us" discount.