Strange/suspicios call to my mobile phone

A few days ago, my mobile phone rang. Though, I answered it immediately, the call was cut off as soon as I spoke.

I was a bit suspicious of calling back (it was another mobile number) as I thought there might be some scam going on. However, I called the number from my land line and heard what sounded like and Australian voicemail message saying, “We are trying to connect you to your contact”.

I’m in the UK and don’t think I know anyone in Oz.

The following day the phone rang once and stopped. I looked at the number, which was identical save for the final digit.

Seems to be more than a coincidence. Anyone got any idea what might have been going on?