Telkom Finrite ****** me

In 2017, I lost my phone (Huawei P10 Lite) due to a hijacking incident and Telkom Finrite replaced it. About a week ago, the replacement phone got ****** and I called Telkom to block my sim which they did but told me they could not blacklist my device because it was registered under MTN, nevermind that this device was given to me by Telkom Finrite and I have been using a telkom contract sim on it. The Telkom agent then gave me the number under which the device is supposedly registered to and i called MTN. MTN agent told me that they needed a formal letter to blacklist the device as the number in question is a business owned number. I then explained to the agent that i had no idea whose number it was and thats when the agent asked me if i had ever taken my phone for repairs. After explaining that this was a replacement phone, he then advised me that he suspected that Finrite had replaced my device with a refurbished phone instead of a new device hence i am having this problem where i cannot block the device. I tried countless times to call Finrite but their agents are forever busy and the longest i have been on the line waiting to be served is an hour. Sometimes, the lines just hang up while still waiting to be served. I need Finrite to sort out this mess as I need an ITC number to open a case and get a case number to be used by my new insurance to process my claim for my lost phone!!!!