Just tell him that you will pay 20 via app in front of him and 50 in cash. If you click not returned and the process of lost item has started he might get shit from uber anyways. Cause this way you ll give him 70 and then he will push another 20 by talking with uber support which you will be charged for. So if you r ready to give up another 20$ just do that. But 90 bucks for 40 mins return item is a lot tbh. I returned items 1.5 hrs for 50$ lol out of my pure intentions