asking about a free quote for double glazing

They called today at 5:40pm just as I was getting dinner ready so i couldn't get to the phone to answer, they left no message.
When I called back at 6:20pm it picked up immediately but was just a busy tone and then it did disconnected?
I have no idea who it was?
Obviously not a proper business or anyone of any importance so just block the number so don't get disturbed in future.

So sick of these people. I don't understand why the Government cannot force the Telcos to stop these calls.

said hello and hang up

Called back, no response. Disconnects.

I called back number (03) 9981 9920 rang once then gets disconnected automatically.