Had 8 veneers fitted but old tooth colour is showing through front 2 teeth and only 3 teeth look the colour they should? (photo)

I arranged with my dentist to have 8 veneers fitted but at the try in my old tooth colour was showing through the veneers, so I had to get my temporaries back on for another 2 weeks (6 weeks in total) while they got sent back to the lab to get thickened. My dentist said this would sort the problem and it hasn't and the old colour is still showing through. I've been in a lot of pain wearing the temporaries for so long. Is it normal to have these problems? What can I do now? Many thanks