If it is only stripped and not sheared off I think VW do a slightly larger bolt which will fix the prob

If the welds have given way & it's just spinning, then you'll have to cut a hole in the footwell!
If you lift the carpet there is a round blanking plate, remove this then cut downwards a little. Then you'll need to weld a replacement nut in there, weld the hole back up & rust-proof the area.