Yellosa rude

Yellosa claiming to be phoning on behalf of MTN . Calling at half past 5 from a Private number. When I asked the very rude call centre "agent" that whether he knows he is phoning after 5 from a private number... He yells in my ear F%&K YOU. ABSOLUTELY SHOCKING that stupid rude people like that are allowed to speak to other human beings like this and hide behind anonymity.