On Time Performance is a big thing for NFI and most of the trucking industry. I'm certain you were warned about being late the first time. If it's something uncontrollable like traffic delays or breakdowns, that stuff happens. But, if it was because you were making unscheduled stops for excessive amounts of time, then that's on you.
In trucking, you have two things to hang your hat on: Safety first, and being on time to the customer. If you can't do those two things then you're not going to be in business very long.