My other programs detected that this number is a number issued by Symbio Networks. This is a company that sells local numbers to scammers. This is the second call from this network with just a 3 digit variant at the end. Rang for 15 seconds then stopped. Possibly wanting you to call back to verify an active number.

This number just got blocked by the spam program, been getting a few calls this week from '03' numbers. Only just started using it so glad to hear it is working well.

Spam call. Second call within 30 minutes.... the first time the end digit was different. Rings for 15 seconds and cuts out. The other number to this has a high spam score, so trying from different numbers once blocked. This one is blocked now too.

21 Jan 2022 4:26pm: They didn't leave a message, possibly because my message says if there's no message left I won't ring back, and if a message is left and I don't recognise the messenger I won't respond. They hang up for some reason.