Hangs up as soon as you answer call

Called but left no message.

Hangs up as soon as you answer

Hang up and left no message.

Keeps calling but never leaves a message. Blocked the number now. Likely a spam call.

A research program attached to hospital as stated above

Caller: Sir Charles Gardener Hospital research

I was too busy to talk, I only answered it to find out who has been calling me every day for a week, it came up on my screen as SHA.

Missed call from this number, no message left. So checked here. Will block number.

unknown number called. I picked up but did not speak - could hear noises in the background but the caller did not speak - just hung up. Must be a scam. Number is now blocked.

Spammers

Caller: Foundation research company

Telemarketing

JUST BLOCK

Hung up when unanswered. Left no message

This number keeps ringing on mobile and landline even though you tell them to stop.
They're after money.

Caller: made some reference to some research company

Treated it as a scam call