Samsung s10 plus

Good day I have a cellphone contract with mtn which i am paying a lot of money for allmost a R1000 a month I have recently upgraded to Samsung s10plus it was just released at the time it was about two months after the upgrade my phone fell and screen cracked days after tha the screen disappeared halfway then few days after it was completely off but the phone was still on i then went back to mtn to ask if the phone is not under warranty and the cant fix it for me they asked me if i have registered the phone on samsung and if i paid for the warranty i said nobody told me about it you have to register your device in 30 days. I am sitting with a brand new device which i cant use anymore and its goin to cost me up to R6000.00 to replace the screen its ridiculous All i want is my phone to be repaired or be replaced i stil have to pay another 15months om a device i cant use such an expensive device but no warranty Its bad from both companies SAMSUNG ASWELL AS MTN PLEASE HELP THANK YOU