Warranty of a phone

My name is Lerato.I live at Soweto i bought a Microsoft phone cash at cell c but after 3 months it wasnt charging.I went back to the shop and asked them how much it was for them to fix my screen cause i knew for charging point it was supposed to be free as a warranty.My phone fell after it wasnt charging and they said couple of rands and i said they can just fix the charging point and leave the screen cause it was too much and they took my phone and said they are sending it to Midrand cell c for repairs and i must collect it after 3 weeks.I went after three weeks and it wasnt fixed i had to contact them at Midrand to ask about my phone i was suprised as they said i must pay R883 for my phone to be fixed and i told them i didn't say they must fix screen but charging point and they say they cant fix my charging point cause my phone is cracked and for that i have to pay...So can you please tell me if really i have to pay like i dont have a warranty because they say their agreement and Nokia doesnt say they should fix for free?I have asked everywhere and they said i am not supposed to pay for them to fix my charging point....