What are the chances of being convicted of robbery in the second degree with no weapon if there it's no evidence?

A former manager of mine texts and calls me asking if I can get him pills. I meet him at his store to pick up the money and leave. I never came back with the money or pills. I presume he got very angered and called the police and made a report saying I came up behind him, pushed him on the ground and grabbed $50 from his wallet.The victim lied to the police in order to get back at me. There is no proof I did anything. It is his word against mine. The police did not find the $50 on me and we were in an area that most likely had cameras around.Is there any chance I can still be convicted without any proof? How do I go about getting the video footage of him handing me the money? Thank you.