I app**** for a data contract and i cancelled before i recived the delivery of the sim card, however, Web africa is ignoring my cancellation and they keep trying to debit me for a sim card i do no have in my possesion

I app**** for a data contract and i cancelled before i recived the delivery of the sim card, however, Web africa is ignoring my cancellation and they keep trying to debit me for a sim card i do no have in my possesion. i sent a request for this contract to be cancelled and i was informed it was cancelled but that is not the case. i asked for confirmation in wring from the consultant who was assisting me but it was not sent. i want them to stop debiting me emailing me invoices for a sim i did not even recieve let alone activate