Contract not cancelled

I called on the 30th of July to cancel my contract ending 31st August 2024. Reference number ***.

This morning I got a message saying that my contract is changing from R117.39 to R154.783 on a month-to-month basis. I CANCELLED MY CONTRACT A MONTH AGO.

I don't even use the MTN number because the network is SO ****!!! So I bought airtime to call and cancel. This morning I had to do the same thing and NOBODY helped me after 20 minutes!!!

Why am I being charged when I cancelled my contract?!?!?