How to explain a mistake on employers part on job application

So in January i was fired for being late repeatedly because i was scheduled at a time that i physically couldn't arrive at, because my grandmother drove me to and from work due to not having a license. I was warned about arriving after my scheduled time multiple times (which was store opening) even though i was arriving within the allotted 9 minutes i was told about when i got the job. Now, I'm applying to a new job after leaving my previous, and i don't know how to explain this incident. This job also had issues with scheduling on days i couldn't work due to volunteering and Doctor's appointments