Unfair terminating of internet

I have a month to month contract with ISP and made an EFT payment on 3 September 2021. My services were terminated on the same day saying I did not pay for August 2021. I asked why no one advise that no payment were received for August because I did not get a invoice and my services were not terminated and they just said sorry for not switching off the internet. Now they switch off for a month that I have paid. I received an email 2days ago saying my services will be reconnected but I am still waiting. I requested to made payment arrangement for August payment and were ignored. I was promised on 4 September 2021 that the person working on my account will contact me and I am still waiting.