Poor service post-sales

On 2 January 2020 my partner bought a Suzuki Alto. He had the car for a month and 5 days then on 5 February he had to take it in because the gearbox broke , it's been 21 days since he took it in and everytime he asks when it wil be done they have a new excuse.He would have gotten it back on Monday 17 February but still nothing. All he gets are excuses. He desperately needs his car. This is not acceptable. Can someone please help him in this regard?