Incorrectly billing clients - *******

I had a month to month data sim card from telkom, I went into the Rosebank branch and cancelled the subscription on 03/04/21. I was advised that the subscription was cancelled immediately. Today I received my latest statement and I am billed the full amount and not pro rata for the 3 days used? I logged a request previously regarding the all network voice data and have not been contacted to discuss the matter. I wonder if telkom reads these messages and respond to their clients - please provide us with the OBS details to escalate our concerns due to no response to social media escalations.