Unfair conduct

I cancelled 2x Telkom contracts on the 2nd of May. I physically went into one of their stores to cancel and o was advised that the cancellation is complete. Today I receive a statement and I am billed for the same contracts that were cancelled. I contacted Telkom to follow up on why I’m billed for cancelled contracts and I’m told that it’s because the data was already allocated. 1. The contract was cancelled on the 2nd and those SIM cards were blocked, no longer working. 2. The blockage of the SIM card on date of cancellation means that I could not use that data even if it was allocated.

It therefore makes no sense that I’m billed after cancellation for services I did not make use of nor had access to make use of.