If it really bothers you and you want the stripe back on then apply the new stripe over the existing one, paint and all. If you try to remove the old stripe it may not come off in one piece and you may peel the paint along the edges causing a jagged edge. If the original stripe isnt peeling or bubbled then go over it. It's a little late to bitch at the body shop IMO. If you want satisfaction have them furnish and apply the new tape as this should have been done originally. Good Luck