DISGUSTING CALL CENTRE AGENTS HARRASSING WITH NUMEROUS CALLS

I have been a customer of Truworths for about 20 years. In July, I missed a payment (thinking I had made a payment - like I always do). On the 10th of August, I received about 5 calls from them. I was at work and did tell them that I would check my bank statement just to make sure. After that, I was harrassed by countless calls from them. I made an arrangement to pay 2 months' installments after the 25th of August. On the 26th of August I made the payment(when my salary reflected) I received 3 calls on Saturday the 26th. I told them I made the payment on Saturday morning. On Monday the 28th of August I received another 2 phone calls, by this time I was furious. I emailed POP@truworths and also sent them the proof of payment. Today the 30th they phoned and harassed me again. I THINK THIS IS ABSOLUTE DISGUSTING BEHAVIOUR - HARASSING ME OVER THE PHONE SO MANY TIMES. IF I RECEIVE ONE MORE PHONE CALL - AFTER I HAVE MADE PAYMENT - I WILL TAKE THIS FURTHER - BECAUSE I THINK IT IS AGAINST THE LAW TO CONTACT A PERSON SO MANY TIMES FOR A SILLY MISTAKE, THAT WAS RECTIFIED. According to what i understand one has until the 7th of a month to pay an account. Do better Truworths