Businesses are being warned to be on their guard against people claiming to be selling advertising space on behalf of the police.
West Mercia Police and Staffordshire Police have assured companies in the area they do not "cold call" on people for advertising.
The callers claim to be working for the police selling space in emergency service magazines, leaflets and wall charts.
In one incident, a company in Bridgnorth received a call from someone who wanted money for an advert in a publication and when challenged the caller became abusive and hung up.
Contact police
A West Mercia Police spokesman said elsewhere in the country companies had been duped into handing over money because they were told it would help the emergency services.
"We do not cold call people seeking advertising nor are we working with any firms doing such work on our behalf."
Pc Jane Jepson, of Staffordshire Police Crime Reduction Unit, said: "We're concerned that people might be parting with money in the belief that they've spoken to someone from the force, and are supporting Staffordshire Police, which is not the case."
Officers urged businesses to ask the caller for their name, address and telephone number and to contact them if they became suspicious.