Body shop painted over vinyl stone guards

Maintenance/Repairs
1 
 I purchased a used 1990 VW Cabriolet four months ago.  The body was in good shape but the paint was faded.  I immediately had it repainted at one of those national franchise body shops.  Although I paid for extra body prep, they weren't really dilligent on the preparation.   Instead of masking the vinyl stone guard on the rear fender, they painted right over it.  One one side the vinyl wrinkled in places.  The other side is bumpy.  It looks horrible.  I should have mentioned something to them at the time but...
 I recently found a source for reproduction vinyl stone guards.  They die cut a 2 mil, high quality, vinyl decal in the exact same shape as the original stone guard.  I am not sure how to remove the old vinyl under the new paint.
 The question is should I try and remove the old vinyl stone guard under the paint or apply the new one over the painted one?   I don't want to ruin the new paint around the vinyl decal during the removal process but I want the new vinyl decal to stick well.  If I remove the old vinyl, is there any advice on how to do it.
2

Have you brought it back to them and requested that they correct the problem?

I’m sure they’ll correct the problem at no cost, but of you do descide on a new decal my suggestion would be to sand the old one and clean it well then apply the new one over it. With help from some masking tape it shouldn’t be difficult to avoid damaging the surrounding paint.

3

No need to sand it off. First take a razor blade and cut around the stone guard as close as you can. Then take a blow dryer set it on high. Then heat it up don’t get it to hot. Lift up the edge using a old butter knife or putty knife and peel it up slow. It will come off this way. Now for what it will look like after is anyone’s guess. If you are lucky the old paint will be a close match.

4

Any place that has an extra body prep feature is not a place to take seriously. The OP knows this now, so I put my comment in here for those who may not. Even if they hadn’t painted over it there may have been damage done. I guess I know why masking tape is made of paper. Now I’m wondering if there are any masking tapes made from plastic. There must be; it is 2012.

5

There’s a blue plastic tape for household interiors.

6

If you haven’t asked already, it is worth asking the paint shop to replace the stone guards. If they balk, tell them you will provide the vinyl guards if they will put them on. It should only take a few minutes.

The blue masking tape is great for interior walls because it is low tack. This helps prevent pulling off paint and paper from the wall. Since there might be abrasion involved in cleaning or removing the stone guards, a higher tack masking tape might be a better choice. If the paint pulls off the body panel, the paint shop needs to repaint the car.

7

I was disappointed with the whole experience. They are unlikely to correct anything. I am going to remove the old decal and not apply it over the new paint job. Thanks for the advice.