Gahhhh! Someone keeps calling me from this number and hangs up!

I have just received a call from this number as above no message and I too am on the NO CALL register!!!

I got a missed call from you Tuesday morning 13/9/11. Who are you?

I had 2 calls from this number on 13/09/11 and just had another call from them then! No message left, its getting annoying.

Received a call from this number and they hung up when I answered.  I don't call back unless I have some idea who the person or company is.

I've had 3 calls from this number and several from very similar numbers in the last week. When I answer they hang up straight away, its says it a call centre of some sort when I ring it it getting very annoying.