Number is ‘switched off or unavailable’

I just had a call from this number a moment ago & no message left on my voicemail.

Can’t call them back. Keeps saying ‘call failed’

A funny voice said they were Alice and something to do with the State Govt, said they weren't selling anything, and asked if I had solar panels.
I was suspicious so hung up.

delay when answers i hung up as no one at other end