No contact to the customer from insurance

I sent my phone in for repairs with the insurance as the glass screen was cracked but the phone and lcd were still working 100%. After a lengthly period of trying to get feedback from the insurance the phone was collected. A month after that I get an email saying the phone is beyond economical repair. Impossible since only the glass screen was cracked. After calling the repair centre because I couldn't get ahold of the insurance I get told that when they opened the phone the motherboard was broken as well as something else but the phone was given to them still fully functional. Also now I have to pay an excess of R650 instead of R350 which was stated on the form I sent in which was given to me by MTN. Then trying to contact the insurance company on that regard and I still cannot get through to them. I phoned head office and they said the number on all the forms and the number that the repair centre gave me has not been working for 2 months. They told me to speak with the call centre. I have done that multiple times and have been told that it has been escalated and someone will call me back. That hasn't happened and it has been almost 2 weeks. I have wasted over R100 trying to call.