Having a debt but being unable to pay it off

The place i live involves people selling on the streets, so it is usual for someone to buy when they are in a vehicle and receive and pay for their products. However, when I was on a bus the seller gave me their product and just as I was about to give them the money the bus began moving because we were in the middle of the road. So the seller began running for his money and I quickly reached out to give him but it landed badly on his hand and fell to the ground. I believe it might have fallen into hole in the middle of the road and the driver of the bus had already gone past the road so the seller could no longer run for his money, and there were too many cars for the driver to pause suddenly, nor do I think the driver knew. I felt guilty because it was not my intention for the money to land badly especially since I had already received the product. I do not remember his face or name, nor do I think he remembers mine. Does this count as a debt if I gave him the money but it landed badly and I don’t know if he managed to get it or not? Especially since he gave me the product? My intentions were not bad and it happened very suddenly