RCS - CTM is such a NUISANCE

I was behind with one installment which I forgot to pay as I had a very busy month in March. I made a double payment on Saturday, 29/03/2025 and I received an sms thanking me and saying that I still need to pay R20 to bring my account up to date. I went to pay R30 yesterday and to my surprise, they sent me another sms today saying, "Despite several reminders, Payment received on your CTM acc remain short. PAY R18.67 TODAY, & avoid added charges." Seemingly they are charging me for the smses and I will accumulate unnecessary costs. I paid them R1300 for heaven sake, and they send me smses left right and center and expect me to pay for that.