Dreadful service form Cell C

I have been a loyal Cell C subscriber since the establishment of Cell C and have always paid by direct debit. Today I received an e-mail saying my payment is late. After 2 very frustrating phone calls to Customer Services, I was advised to ask them via e-mail to rectify the expiry date on my debit card, since I was never debited me on 30 April, as should have been the case and apparently they have the expiry date on my Mastercard as May 2024, whereas it expires in August 2024. I have confirmed with my bank that a card is valid until the end of the month in which it expires, so, even if my card did indeed expire in May, I could still be debited it until the end of May 2024, unlike the advise that I have been given by Cell C telephonically i.e. that they could not get their system to debit my card, again, according to them, because it expires at the end of May 2024.

I consider this breech of contract from their side and view this in a very serious light. I am not responsible for system errors on side of Cell C systems, Their error reflects negatively on my creditworthiness.