They are so unprofessional

I am not happy about the billing and customer service department, I am paying my account on monthly basis. Yesterday received sms notification that I owe R152 and they cutting my services if I don't pay by the end of the day. I quickly call them and sending the proof of payment that my bill was paid on the 29/07/2024 for the month of August, and their response was that there was an increase from the beginning of June of which I was not informed about. I ask for the email informing me about the increase and I didn't get the email, and I am really not happy about that. I still need the email claiming that they sent to me, or notification of the increase. I searched all my emails from the beginning of March and there is no such email