Conflicting Answer from Call Center

I received an sms on the 16 Jan, 22 Jan and 26 Jan stating that my payment is overdue and I needed to make a payment urgently. Payments are paid diligently every month before month end, so why have I received such an sms.I contacted the call center and enquired and they advised that this is due to the statement closing date being the 15 of every month, hence the sms was received. So then means that after every closing statement date an sms of overdue payment sms is sent to client , the lady said this is correct as this is a just a reminder. Funny, I have not received such an sms before and yet I am client of Standard bank for a long time and I have been making payments around the same dates. By the way the one of the sms stated: you must pay urgently as this may affect your credit rating! Please sort out your transactions and stop sending me such sms and ensure that this does not affect my credit ratingI I would appreciate it if someone with contact me and give me a reasonable answer as to why I received this sms !