Want to know if your rental was cancelled? Go to Peakmonsters
Peakmonsters will show of the cancelled rental/s and the time remaining for it to used. I notice that Splinterlands card rentals does not show this one. You can also extend your rentals here.
You can used Peakmonster to monitor your rental/s, just log in at https://peakmonsters.com/ and go to My Cards section.
If your rental is cancelled, it will show off a question mark on the Delegated to (Rent remaining) Tab. Just click that tab in order to arrange it and easily see those cancelled ones.