Car smells so bad

I got my car serviced from Mahindra (30K kms) and they did such a bad job of cleaning that I complained and they took it again the next day. I paid 12.5K rs for this service. Now the problem is the car smells so bad that even my car freshener isn’t working and it’s difficult to drive without the windows down. They didn’t solve that problem even after taking the car again. Any solutions for this?