MTN *****ed business

I bought P40 lite Huawei phone 2years ago it was a contract and it was insured with MTN insurance i paid my insurance for 2 years till it was time to upgrade then after upgrade i continued with the insurance and my phone got screen damage and i claimed and they took forever to respond and after a month after my claim they told me that they cant fix my screen as the sim card that was inserted was not the Sim card insured and I had 2 MTN number insured with them witch i always used because i couldn't wait for them i fixed the screen, after few months i got ****** i lost my phone i also claim it without any assessment done i was told that my claim has been declined due to the fact that i used different sim card and ii still say sim card that was used on that phone was MTN sim card and the contract numbers that I bought with the phone, MTN is **** and they stole my money for 2 years and unable to help and they were so quick to cancel the insurance after my phone lost without even showing me the proof of their assessment. Please Help