Unknown number called me but did not leave a message. I rang back immediately but got engaged tone. I suspect a scammer.

When this call was answered there was a short period of silence, then the caller hung up. When I called the number back (a couple of times) there was an engaged signal. I suspect is was a scammer (possibly automated) which was just continually calling numbers.

The third unsolicited call from an unrecognised number to my landline today. No message left. Reporting here as suspected scam or telemarketing call.