Rude and lack of customer care

I had twins recently and was unaware that there were blood tests taken that weren't payed for by medical aid. 4 MONTHS LATER lancet contacted me (the lady was beyond rude from the hello on the phone) saying I needed to pay R1300.00 odd rand immediately so that my account isnt handed over. I complained that it was unacceptable to call me in the middle of the month, demand immediate payment, and not ever let me know before that I owed them money despite having all my details on the system. I said to her that I'll pay them half the amount now and half at the end of the month, she again said this wasn't allowed and had to pay immediately, again I said it was unacceptable and she abruptly ended the call telling me not to worry, my account will be handed over to attorneys.... ****** useless.