Missing Venmo Payment

[Curt Bixel]

I have three new tenants that cannot pay be check, because they have no checkbooks.  The property manager previously had things set up for them to pay through a online portal, but the property manager is no longer involved and I have inherited the lease.  I have no online payment portal, and am in the process of setting one up, but it is not yet ready.

The tenant suggested that we could do this by Venmo this time to provide time for the portal to get setup.  

Now their Venmo interface shows the money being sent to me, and my interface shows the money not being received by me.  I have contacted Venmo, and they say that the issue is that the tenant did not completely complete the transaction on their phone.  The tenant says that they have.

I am assuming at some point Venmo will be able to figure this out and get the transaction completed, as it does not in any way appear that the money was sent to someone else incorrectly.  

If, however, Venmo cannot figure it out, who will end up being legally responsible for this missing money?