This is a scam. They ring first on a blocked number saying that you agreed to advertise in the Volunteer Rescue Magazine a couple of months ago (which I never did) and then a second call comes from this number and says that they are ready to post the invoice. I just said I wish to cancel this as I googled you and found out you are a scam and if I receive any further communication I will report you to the ACCC under Scamwatch. The lady didn't have anything further to say.

I have just had this no ring me.saying I have an advertisement with an invoice for 286. I dont recall agreeing to this. What can I do

Scammer, says they are from a (fictitious) magazine, Volunteer Rescue Magazine, and insist you have ordered advertising and ask you to pay.