Mtn giving faulty \refurbished"handset"""

I am extremely angry and dissatisfied with the service from MTN Insurance and Mtn Repairs. I insured my iPhone with MTN and when i claimed for a cracked screen my handset was replaced with a \Refurbished Handset". Now this refurbished handset has been giving me problems for months. it started with a faulty speaker of which MTN repairs said they can't find fault with it and I had to pay R330 coz they didn't find fault (according to them it's a network problem). How is it a network problem when I'm the only one experiencing funny noises during phone calls and i cannot hear the other person on the other end. Now this morning I woke up to a frozen phone which i can unlock (thanks to finger print ID) but I can't swipe it. Why am I paying for a phone that I can't use?<br> <br> MTN promises the moon and stars when they call us wanting us to insure with them"