01612350402

Rung morning and afternoon for three days, just two ring then rang off.  Not willing to dial an unknown number

that number called here today too I never even heard it ringing

This number rang  2 rings then off , unknown so did not answer

This number rang my mobile this morning. I had it flagged as suspected spam, so didn't answer. No message was left on voicemail.

Caller said "hello, I'm Ellise from AO.com...", she cut the call at her end but left the line open.
I couldn't ring out from my line, but could ring in.
After calling phone engineer from my phone service provider, turns out that their line test reset my phone line for me.
Be careful not to make calls after receiving one from this number, as it is suspected they could be listening in.