Bad Treatment from DMC

I received an email from DMC on the 2 Dec 2024 to say that prescribed debt from Capitec has been bought by them and they want to make a payment arrangement. While I am busy investigating and checking this, they sent someone to my place of work the next day without informing me the person is coming and the guy threatened me that legal action will be taken if I refuse to make an arrangement which is *******. This is very unprofessional assuming that we don't know our rights.