Fixing the NES is not even nearly as complicated as messing with the xbox. All you do is pull off the old connector and slide on the new one. It will probably be cheaper to get one and replace it yourself.
I had a topic about it many months ago. Give them a call at their toll fre number. Tell them your nintendo is messing up and you need a new 72 pin connector. Some people have had problems getting them, if so just try again. If I can find the original post I'll link it.