They are treating you right. Tightening up the covering on an ARF is standard procedure. It is not possible for every ARF to arrive with tight covering. And if they tried, our costs would increase substantially with the extra time and labor involved in putting the covering on that well. The end user has to iron down the edges and shrink the covering in a few places. You did it wrong, and they are offering to send you new covering to fix it. If you trim the bad covering off neatly no one but you will know that the plane has been worked on.