It is a crime where the caller pretends to be from an advertising agency and offers advertising space in their publication. The publication is often bogus, but the caller creates an impression that it has partnered with charities, crime prevention groups and emergency services or offered community health initiatives. 

They may even claim the target firm or their representatives have agreed to their offer and ordered the ad space in their publication, and they ask the victim to pay the charges for the services. 

Finally, they send invoices where all the agreement details are mentioned, and they may threaten legal action if their bills are not paid. 

Most such organisations represent charities, rehabilitation projects, 999 services or rescues. 

They sometimes send office stationery or products to a business organisation, claiming they received an order for the product delivery from the staff of the client firm. 

Then, they use pressure tactics to get their invoice cleared. Sometimes, they ask the victim to transfer funds into their bank account. 

Sometimes, the clients pay the money even when unsure if they ordered the ad space or the stationary. However, do not pay the bills and report the crime to the investigatory offices if you suspect such publications.