Police are urging people not to trust any company that claims to be working with Sussex Police.
A spokesman said: “The force and Trading Standards officials have been contacted by residents who have been called by a company called Direct Response Security.
“The company’s representatives have falsely suggested the firm is working with Sussex Police and that by signing a contract to have one of their alarms fitted, residents will have direct access to a nearby police patrol at all times.”
Chief Inspector Martin Sims said the force did not have an arrangement with alarm companies or any similar businesses.
He added: “If a member of the public calls 999 or 101 they are responded to based on the seriousness of the emergency, not whether they have an alarm or not.
“Do not accept the claims of any company that suggests it is approved by or linked to Sussex Police. If you hear such claims, please report them to us.”
Call 101 or email firstname.lastname@example.org.