Simple request dragging unnecessarily

I'm finding it very hard to find someone competent at MTN to assist me. Last year when I was moving houses, one of the phones I have got lost in the process. I then contacted MTN and asked them to block both the SIM card and the phone since I didn't want it to end up in the wrong hands. I was assisted promptly and all was dandy. A few of weeks ago I discovered the phone in one of the boxes and I contacted MTN helpline to assist with removing the phone off the blacklist. Geez, this was the start of my nightmare. The agent that was assisting me said that I needed to send through an affidavit, proof of contract and the IMEI number of the device (Just to prove something that they already have). Much to my objection, I obliged and sent through everything that was requested. I have sent multiple emails to the agent and she's not even acknowledging my emails. I honestly think this is a ******* as I had never missed their debit order and I'm honestly not happy with the service I've received. Can someone competent please assist me?