Telkom cellphone and router contract

I took 3 contracts with Telkom, one of the contract ended in May, however, they continued sending me data and I was not aware of this as I didn't have the phone with me. They charged me for those months and when I enquired they said I should have cancelled a month before my contract ended. This is a total rip of because they manage to remind customers to upgrade but they don't remind them to cancel. If I took a 24 months contract it means if I don't upgrade then you terminate services. With MTN it's like that. I totally think Telkom is ripping us this way.