Catch 22 - Catrack demand personal information without reason for call

I am getting daily calls from persons claiming to be from Cartrack accounts department, demanding I provide personal information prior to them informing me the reason of the call. Maybe its a catch 22 situation, but Im NOT providing you personal details, unless you give me the reason for the call!!!. Dont hide behind Popia act! Furnish the reason for your call, Ind I will decide whether I continue with the conversation.