Do you possibly have a friend or relative that might be able to give you a ride, or even a friend or relative that could drop it off at UPS for you?
Another idea is local businesses, especially if you know one well. Sometimes they will take a pre-paid package for you and give it to the UPS person when they give their own shipments to them. There's also the possibility that there is a local business that offers this service for a small fee. We have one that does this for $1. Our closest UPS place is 24 miles from here, so what this business does comes in very handy.
You cancelled the service and got the return equipment box with the prepaid UPS label, right?