If the paint is classed as an optional extra, then write a letter to the dealership HQ and ask for it back as the vehicle is faulty, consumer rights.
I did this with a faulty Tiguan I had, MB gave me AP pro rata’d I then sought optional extras back from dealership as no contract was formed or signed in regard to these being paid for separately.
My complaint went to VW Compliance team in Germany and they got back within 48 hours stating I could have the money back so long as I signed a non fault agreement and would not pursue them in future for the issues I had as I was seeking damages too. I agreed as it was over £1200 I was seeking back.
So that’s a consideration but do it after they have had the car back and you have ordered something else with MB as they may contact MB, MB will say the same to you as to the dealership its nothing to do with them.
But it is possible, prepare for a fight though. Ive ordered a new car and had minimal optional extras because of this.