We took a look but could not find parts for the Harbor Breeze Riverview ceiling fan. As you said, it’s discontinued so finding parts can be tricky.
Couple of options…
1) We see the fan is actually on sale for around $100 (clearance sale) at major retailers, so you could try that route and just replace the fan if you really like it and just want another one
2) Although this is a little bit more sneaky and we’re not condoning this, some people do it….you could buy one of the clearance fans, mount that, put the broken fan back in the box and return it. Or just remove the parts you need etc.
That’s if they let you return a clearance fan. Make sure you check first