Pesky sales calls

We understand that everyone has to earn a living somehow but we have really noticed since the end of last year there has been an increase in the amount of sales calls we get - for services we are never going to use! We try to be polite on the phone but sometime wonder why nobody researches companies before calling them?! Just for the record we don't need work uniforms, don't make international calls, don't need travel arrangements and we do not want to switch our suppliers! Ok, rant over now!