Just a heads up, most offices don't carry cash now and you'll need your bank account details if they don't already have them.
No Medicare offices carry cash at all anymore. It's all registered bank accounts only or as Doing my Best explained.

The Lilydale one appears to be a combined Medicare and Centrelink, the address is below and it looks like it would be closed. There is one in Eastland shopping Centre

Cnr Anderson Street & Chapel Street

Lilydale VIC 3140