wheel locking nut removal having difficulty removing front driver side wheel. This nut keeps slipping

 

Those are used on everything, so it's not entirely a volvo question, but the volvo studs with the big tapers do have a lot of contact area.

There are professional removal services for those everywhere. Even with the damage to the key you've already done, you might still be able to bring it if you use lots and lots of force to maintain as much engagement as you can, but you probably don't need me to tell you that. Every person who ever used a phillips screwdriver has already lived through that situation.

 

nice one !