Mtn charging subscription fee without letting customer know

On the 18th of May, I received my contract Simcard for the 5G data deal I took with MTN. Due to lockdown, the contract was finalised telephonically. Today I get my state and I'm being changed R195 subscription fee which I was never told about. I was aware that data will be charged pro rata but not even one mention of the subscription fee. All calls are recorded right? I request the phone call where an MTN service champion told me about the subscription fee because I refuse to pay it.