REVCO Tshepo Themba hospital account

the experience i keep on receiving from REVCO is the worst experience ever. I made an arrangement of paying monthly payment of R500 until i settle the debt. In January 2021 i did not get paid, they phoned me days after the debit order was returned unpaid, advised the consultant that she can reschedule payment for 20 February 2021, she agreed. on the 20th February payment was not done, they called me again, when i ask why they didn't deduct as per January agreement, the consultant gave me a very stinky attitude asking me how were they supposed to know that they should deduct, when i try to explain he continued to be mean, they started sending me threatening messages. i told them to continue with deducting R500, we agreed that on the 20th April 2021 they will continue with deducting R500, i spoke to 2 consultant, on the 20April 2021, 2 deductions went off of which was not part of the agreement,its basically *****, i reversed 1 R500 meaning i paid the agreed amount of R500 not the R1000 that they deducted, after that they wanted me to settle the whole R19000+ within 48hrs, that message was followed by a lot of threats of being listed on the credit bearue, the last message stated that my name have been sent to credit bearue and this month on the 20th May they did not deduct. what kind of service is this?