Keeps calling, then hangs up as soon as I answer. Maybe someone checking to see if I'm at home. Once I heard an exclamation that I thought sounded like "Oh no!" or something similar. This has been happening for a few days now.

Didn't pickup. They did not leave a message. Now they are marked as spam.

Caller: Charity

Rang for Epilepsy Australia - Can't remeber the agent company name

They hung up as soon as I said "hello". The call was to my mobile so it can't be checking whether I'm home.

Caller: Apple Marketing for Oxfam

I said I give once per year and not when I'm called. They said they weren't asking for a donation. I asked them not to call me again.

Caller: Hang up when answering machine starts

Just called twice in 3 hours

Called me today. I didn't answer. So they still at it.

Multiple calls and I hoped I’d get a message left eventually - finally picked up the phone on one call to be immediately hung up on. Mark it as spam, best thing you can do for your sanity.

They calls, but if you pickup, you hear only silence.

Just called and didn’t leave a message.

Twice in the last five days. I don't answer and no message left.

Keeps calling but never leaves a message.

They keep calling me but never leave a voice mail - I have "Silence Unknown Callers" set on my iPhone

I have "Silence Unknown Callers" set to "On" on my iPhone so these calls go straight to voice mail, buy they never leave a message.