Sometimes I think that a few people in customer service that are like that should be a janitor instead of in that position. The only way it can be cured is to go up the ladder all the way to the President of the company if you have to by letter or email so that someone in authority can look into things. To answer your question about putting it on for free I would say if it's just a simple on/off, then yes. If it takes tools or any length of time, then no, not unless it's being replaced because of a defect in the original barrel.