Unhappy about reduction in Credit Card limit

I would like to complain about Woolworths Financial Services with whom I have a Credit Card. My limit was approved at R20 500. Last week I received an SMS from them stating my available balance, which did not make sense,as it should have been a lot more. I phoned them today and was informed that my limit was reduced to R5 100. The reason for this is because I paid them late this month and apparently earlier this year on 2 occasions. Having said this,yes I was at fault,but I paid my account - this all during the Covid Pandemic,when things have been financially stressful. When I asked them why I never received any correspondence regarding the reduction in my Credit Card limit, I was told that they don't need to do that. This is the first time in my life that I hear that one's credit gets taken away just like that - no email correspondence or any warning letters. I worked for a Bank for many years and this is definitely not how things are done. I also asked the gentleman that I spoke to,to send me an email with the details of my late payments and also the Woolworths Complaints Dept email address. Well, I have still not received it.