Makro (RCS) accounts card division shortcomings

Makro (RCS) sends me an sms 09 October 2020, " A reminder that your Makro account card payment was due 1st of the month & that payment can be made at any Makro store. For queries call ***" at 02:31 AM. I contacted them at 08:58 AM regarding the sms as I have made a payment for September on the 9th of the month. The consultant informs me that payments are due by the 1st of the month, yet the customer has until the 12th of the month to make payment. This 12th is the date for Makro's system to generate your invoice. Now I am told that the payment has gone off the balance but it cannot be reflected as my September payment. My installment for August was made 21 August and for July, 15 July. I am in advance yet they will be handing me over to the collections department to recover September payment. There is no logic in me having an advance payment allocated yet i am in arrears. The consultants manager gave the same feedback and just says that, that is how it is and works.