Immotional abuse

I had a doctor's account which was handed over to Nicol, Davis & Associates for and operation done in october 2020, amount outstanding was R900 and they want me to pay 1800. they told me I have an account and the payment option that i have to choose after i have chosen the option the lady told me to pay on the same day i told her i told have money on that day and when check the amount required is actually double of the doctor and there is no discount as they claimed to give me. a days after i have recieved an sms treatning they have confirmed my employment and they will proceed with the judgement, I fail to understand