Seatbelt is too small

My mother bought a Hyundai Creta in September Hyundai King William's Town branch - she informed the Sales Manager (Wayne Els) that the seatbelt is too small for her to wear. Wayne insisted that she must take the car and the seatbelt will be replaced in few weeks. Its been months of false promises Wayne doesn't contact with feedback. I even contacted Wayne in December but he made excuses about lockdown but he was able to sell the car during lockdown. He was rude telling me that he can send me proof of the order if I want it. My mother is unable to drive her new car because of this. I need the company to resolve this as soon as possible or take back the car.