You shouldn't be a jerk and harass no.
You wasted your own time by not taking the 30 minute hit, and then you would still be ahead one hour.
As long as you were not being a jerk and harassing, and actually trying to be helpful, then you did the right thing and the other guy was at fault for getting angry. Going by your tone doesn't sound like you were being pleasant with your helpfulness.
If your time is so limited and precious then Duty Finder is not for you. Find some friends, LS, FC.... Don't count on DF to find you 3 perfect party members.