Cell C device insurance *******!!!!

I called on the 27/05/2024 and cancelled my device insurance. I paid in advance so I already paid for cover up Until the 31/05/2024. I was advised by Kgomotso at device claims that they will still make a deduction on the 31/05/2024… This is not right because I don’t want cover for June and I already paid for May so why am I being debited for the insurance for June 2024…Cell C is trying to rip me off and I am upset and this is not ethically correct. I need assistance with someone who can help me please