Good morning dear mam/sir,
It is always important and good to have a long term relationship with your doctor or dentist.
You both have to mutually trust each other.
In this regard, if you have any issues with the treatment, it's good to go back and sincerely raise your genuine concern with them. They will understand and sort the problem out. No need to be scared, no need to question their functioning etc. It's a very simple issue with your fillings and nothing of much concern.
In case, they don't respond correctly, look for someone else, who is good.
The issue you are facing can happen with any dentist working on similar cases as of yours. So don't worry.
Next Steps
You can get your issue corrected with the approach I have suggested above.
Health Tips
Dentists work based on allotting work to their associates based on what they are good at and they know whom to give what work.
In case, you have specific choice of a dentist, you may tell them that and get your choice of dentist.
But, my advice to all patients is to give freedom to your doctors or dentists in their functioning, but you may put across your genuine concerns too and get them fulfilled.
Ultimately we want to give you the best treatment, and you too can genuinely ask for that.